Arihant Science Class 10 Term 1 Sample Paper

144 CBSE Sample Paper Science Class X (Term I) 26. The four solution A, B, C and D are taken and their concentration of H + ions are recorded. H+ concentration ABC D Solutions Which solution has highest pH value? (a) A (b) B (c) C (d) D 27. The diagram shows the ways to observe the effect of heat on FeSO4 crystals. (I) (II) (III) (IV) Choose the correct way to observe the effect of heat on FeSO4 crystals and the reason behind it. (a) II-The poisonous gases are harmful to be inhaled (b) III-The bubbles of any gas can come out of test tube (c) I-The mouth of the test tube is hot (d) None of the above 28. Four metals Zn, Fe, Cu and Al are taken and added to the following solutions one by one. The results obtained are tabulated as : Metal ZnSO4 (aq) FeSO 4 (aq) CuSO 4 (aq) Al 2 (SO 4 )3 Zn – Displaced Displaced No reaction Fe No reaction – Displaced No reaction Cu No reaction No reaction – No reaction Al Displaced Displaced Displaced – From the above data, the decreasing order of reactivity of given metals is (a) Al > Cu > Fe > Zn (b) Al > Zn > Fe > Cu SAMPLE PAPER 5 (c) Al > Zn > Cu > Fe (d) Al < Fe < Cu < Zn 29. Amit checked the odour of onion juice and then he added few drop of onion juice in dil. HCl and in dil. NaOH solution in separate test tubes. What would he observe ? I. Odour of onion juice in sodium hydroxide get vanished. II. Odour of onion juice in dilute hydrochloric acid remained same. III. Onion acts as olfactory indicator. IV. The smell of onion was unpleasant. (a) I and II (b) I and III (c) III and IV (d) I, II and III

CBSE Sample Paper Science Class X (Term I) 145 30. A coating on zinc will be observed in Iron Zinc Copper Aluminium sulphate sulphate sulphate sulphate I Zn II Zn III Zn IV Zn (a) I and III (b) Only I (c) Only II (d) III and IV Direction (Q. No. 31 to 34) Consist of two statements – Assertion (A) and Reason (R). Answer these questions selecting the appropriate option given below : (a) Both A and R are true and R is the correct explanation of A. (b) Both A and R are true, but R is not the correct explanation of A. (c) A is true, but R is false. (d) A is false, but R is true. 31. Assertion Zn + 2HCl ¾® ZnCl2 + H 2 This reaction is an example of displacement reaction. Reason Zinc being more reactive than hydrogen, can displace hydrogen from its solution. 32. Assertion Weak acids have low electrical conductivity. Reason The concentration of hydrogen ions is equal in strong acids and weak acids. 33. Assertion Translocation of solutes takes place across the phloem. Reason Solutes can be translocated both in upward and downward directions. 34. Assertion The height of an object is always considered positive. Reason An object is always placed above the principal axis in upward direction. 35. Four students studied reactions of zinc and sodium carbonate with dilute hydrochloric acid and dilute sodium hydroxide solutions and they presented their results as follows. The ’3’ represents evolution of gas whereas ‘O’ represents absence of any reaction. HCl Zn Na2CO3 Zn Na2CO3 NaOH P P HCl PO P O NaOH PO HCl NaOH I II Zn Na2CO3 Zn Na2CO3 O O HCl PP OO P P NaOH III IV The right set of observations is given by student SAMPLE PAPER 5 (a) I (b) II (c) III (d) IV 36. The heart pump blood to transport oxygen from lungs to various body parts. Which sequence is the correct path for the flow of blood? (a) Right atrium ® right ventricle ® aorta (b) Right atrium ® aorta ® right ventricle (c) Left atrium ® aorta ® right ventricle (d) Left atrium ® left ventricle ® aorta

146 CBSE Sample Paper Science Class X (Term I) 37. Choose the function of the pancreatic juice from the following (a) Trypsin digest proteins and lipase digest carbohydrates (b) Trypsin and lipase digest fats (c) Trypsin digest proteins and lipase emulsified fats (d) Trypsin and lipase digest proteins 38. Which of the following statement is not true about respiration? (a) The gaseous exchange takes place in alveoli (b) Carbon dioxide is more soluble in water than oxygen (c) In humans, the respiratory pigment is lymph (d) Rings of cartilage are present in the throat to ensure that the air passage does not collapse 39. A doctor has prescribed a corrective lens of power + 1.5 D. Find the focal length of this lens. (a) 1.5 m (b) 0.67 m (c) 15 m (d) 2.3 m 40. The refractive indices of four media P, Q, R and S are given in the following table: Medium A B CD Refractive index 1.33 1.50 1.52 2.40 If light travels from one medium to another medium, then which one of the following is true? (a) Speed of light in medium D is more than speed of light in medium C. (b) Medium B is the rarest medium. (c) Speed of light remains same in all mediums (d) Medium A is the rarest medium. 41. The liquid waste product of plants formed due to oxidation of various essential oil is (a) gums (b) latex (c) resins (d) tannin 42. What will happen if the undigested food is kept too long in our large intestine? (a) The undigested food will become dry and hard (b) The undigested food will be completely digested (c) The undigested food will get absorbed by the wall of large intestine (d) The undigested food will get stuck in the large intestine 43. A ray of light falls on one face of an equilateral glass prism at 40° and emerges from the other face at the same angle. The deviation suffered by the ray is (a) 60° (b) 40° (c) 20° (d) 90° 44. In case of normal incidence, what would be the angle of deviation through a glass slab? (a) Maximum (b) Minimum (c) 90° (d) 0° SAMPLE PAPER 5 45. 50 cm F P 20 cm Screen Examine the above diagram. At what range of distances should a candle flame be held from the mirror to obtain its real image on the screen? (a) 0-20 cm (b) 20-40 cm (c) 40 cm (d) 50 cm

CBSE Sample Paper Science Class X (Term I) 147 46. 45º Incident ray 45º The minimum refractive index of the prism given above for total internal reflection should be (a) 3 (b) 2 (c) 3 (d) 3 2 2 47. A F2 B' 2F2 2F1 B F1 O A' The above lens has a focal length of 50 cm. The object of height 10 mm is placed at a distance of 60 cm from the pole of lens. Find the height of the image. (a) - 5 cm (b) - 30 cm (c) 5 cm (d) - 6 cm 48. Element Lustre Hardness Heat conductivity A No Soft Poor B Yes Soft Good C Yes Hard Good D Yes Hard Poor Which of the above elements can be used for making utensils? (a) C and D (b) A and B (c) Only B (d) Only C Section C This Section C consists of three Cases followed by questions. There are a total of 12 questions in this section. Attempt any 10 questions from this section. The first attempted 10 questions would be evaluated. Case I. Two test tubes are taken with different solutions, copper sulphate and iron sulphate solution. Observe the two test tubes A and B in the diagram given below and answer the following questions. Cork Test tube stand SAMPLE PAPER 5 Thread Copper wire Iron sulphate solution Iron nail Copper sulphate solution A B Test tube Test tube 49. Which type of reaction is involved in test tube A? (a) Decomposition (b) Combination (c) Displacement (d) Neutralisation

148 CBSE Sample Paper Science Class X (Term I) 50. Which of the following is the balanced equation with correct physical states occurs in test tube A? (a) Fe(s) + CuSO4 (aq) ¾® FeSO4 (aq) + Cu(s) (b) 2Fe(s) + 2CuSO4 (l) ¾® 2 FeSO4 (s) + Cu(s) (c) 4Fe(s) + 3CuSO4 (aq) ¾® 4Fe2O3 (s) + 3CuS (s) (d) 2Fe(s) + 2CuSO4 (aq) ¾® 2 FeSO4 (s) + 2Cu (s) 51. In test tube B, which of the following statement is correct? (a) Copper will displace iron from its sulphate solution (b) The colour of the solution will change (c) The temperature of solution will increase (d) No reaction take place 52. What will be the change in colour in test tube A? (a) Green ® Colourless (b) Blue ® Light green (c) Blue ® Dark brown (d) Brown ® Colourless Case II. Human heart acts like a pumping machine in body that pushes out the blood into the blood vessels. It is situated between the lungs slightly towards the left side of the chest. Human heart is four-chambered. These chambers are meant to prevent mixing of oxygenated and deoxygenated blood. The diagram given below is the longitudinal section of human heart. D C E F AB 53. Part A and part B are separated by (b) interventicular septum (d) muscles (a) valves (c) capillaries 54. Right atrium receives blood from (a) pulmonary aorta (b) pulmonary veins (c) inferior vena cava and superior vena cava (d) pulmonary artery SAMPLE PAPER 5 55. What is the function of part D ? (a) It receives oxygen rich blood from right ventricle and circulates it to various body parts (b) It receives carbon dioxide rich blood from lungs and circulates it to heart (c) It receives oxygen rich blood from the left ventricle and circulates it to various body parts (d) It receives oxygen rich blood from the left ventricle and circulates it to the lungs 56. What is the difference in the composition of blood in parts C and F? (i) C—Pulmonary artery, having deoxygenated blood (ii) F–Pulmonary veins, having deoxygenated blood (iii) C—Aorta, having oxygenated blood (iv) F—Pulmonary veins, having oxygenated blood Choose the correct option. (a) (i) and (ii) (b) (ii) and (iii) (c) (iii) and (iv) (d) (i) and (iv)

CBSE Sample Paper Science Class X (Term I) 149 Case III. Raman wanted to know about the uses of convex mirror. On learning, he understood that a convex mirror is also a simple way of improving the safety in our warehouse or production environment. In a work environment or warehouse, convex mirrors can be placed at crossing or blind spots to enable workers to see approaching for lifts, other vehicles or approaching colleagues. This provides employees with the necessary overview of their work environment and therefore, increases the safety in the workplace. 57. When Raman tries to move object away from the convex mirror, he noticed that the size of image (a) increases with distance (b) decreases with distance (c) does not change (d) is same but brightness decreases 58. The image formed by a convex mirror of focal length 30 cm is one-quarter of the object. Select the row containing the correct value of object and image distance. Object distance (u) (in cm) Image distance (v) (in cm) (a) - 90 + 22.5 (b) - 22.5 - 90 (c) - 90 - 22.5 (d) - 90 + 90 59. His friend noted some properties of convex mirror with this demonstration. I. Convex mirror always forms a virtual and erect image. II. Convex mirror may form real or virtual image depending upon the position of object. III. Convex mirrors provide wide field of view as they are curved outwards. Which of the above mentioned properties, a convex mirror has due to which it is used as rear view mirror? (a) I and III (b) II and III (c) I and II (c) I, II and III SAMPLE PAPER 5 60. An object of 7 cm in length is placed at a distance of 20 cm in front of a convex mirror of radius of curvature 30 cm. The size and position of image formed are respectively (a) - 3 cm, + 60 cm (b) + 3 cm, + 60 cm 7 7 (c) + 3 cm, + 7 cm (d) - 3 cm, + 7 cm 60 60

OMR SHEET SP 5 Roll No. Sub Code. Student Name Instructions Use black or blue ball point pens and avoid Gel & Fountain pens for filling the OMR sheet. Darken the bubbles completely. Don’t put a tick mark or a cross mark, half-filled or over-filled bubbles will not be read by the software.  Correct Incorrect Incorrect Incorrect Do not write anything on the OMR Sheet. Multiple markings are invalid. 1 21 41 2 22 42 3 23 43 4 24 44 5 25 45 6 26 46 7 27 47 8 28 48 9 29 49 10 30 50 11 31 51 12 32 52 13 33 53 14 34 54 15 35 55 16 36 56 17 37 57 18 38 58 19 39 59 20 40 60 Check Your Performance Score Percentage = Total Correct Questions × 100 Total Questions: Total Questions Total Correct Questions: Less than 60% > Average (Revise the concepts again) If Your Score is Greater than 60% but less than 75% > Good (Do more practice) Above 75% > Excellent (Keep it on)

CBSE Sample Paper Science Class X (Term I) 151 Answers 1. (a) 2. (b) 3. (a) 4. (d) 5. (c) 6. (b) 7. (b) 8. (b) 9. (a) 10. (b) 11. (d) 12. (b) 13. (b) 14. (d) 15. (b) 16. (c) 17. (d) 18. (a) 19. (b) 20. (a) 21. (c) 22. (a) 23. (d) 24. (b) 25. (c) 26. (a) 27. (a) 28. (b) 29. (d) 30. (a) 31. (a) 32. (c) 33. (b) 34. (a) 35. (a) 36. (d) 37. (c) 38. (c) 39. (b) 40. (d) 41. (c) 42. (a) 43. (c) 44. (d) 45. (b) 46. (b) 47. (a) 48. (d) 49. (c) 50. (a) 51. (d) 52. (b) 53. (b) 54. (c) 55. (c) 56. (d) 57. (b) 58. (a) 59. (a) 60. (b) EXPLANATIONS 1. Gas is evolved vigorously in both beakers. 8. Ammonium sulphate is obtained from In beaker I, 2HCl + Zn ¾® ZnCl2 + H2 ­ ammonium hydroxide (parent base) and In beaker II, 2NaOH + Zn ¾® Na2ZnO2 + H2 ­ sulphuric acid (a parent acid). H2SO4 + 2NH4OH ¾® (NH4 )2 SO4 + 2H2O 2. When calcium oxide is treated with water, then calcium hydroxide is produced along with heat. (Parent acid) (Parent base) CaO + H2O ¾® Ca(OH)2 + Heat 9. In chlor-alkali process, the reaction involved So, this reaction released heat, hence it is exothermic. + Electric current 2NaCl 2 H2O ¾¾¾¾¾¾® 2 NaOH + Cl2(g) + H2(g) 3. When metal oxide is reacted with acid, it forms So, the products formed from this process are salt and water. e.g. CuO + 2HCl ¾® CuCl2 + H2O NaOH, Cl2 and H2. Fe2O3 + 6HCl ¾® 2FeCl3 + 3H2O MgO + 2HCl ¾® MgCl2 + H2O 10. The reaction between CaO and water is ZnO + 2HCl ¾® ZnCl2 + H2O exothermic in nature. There is no evolution of gas. Hence, change in temperature take place in the Hence, option (a) is correct. mixture and the container gets hot as heat is released during the reaction. 4. When lead tetraoxide is heated, then lead 11. The correct labelling is W = Larynx oxide and oxygen gas produced. This lead X = Trachea Y = Bronchioles oxide is yellow in colour. Z = Bronchus ¾¾D ® 2Pb3 O4 6PbO + O2 Bronchus are main passage way into the lungs. It further get divided into smaller bronchioles. Lead tetraoxide Lead oxide The incorrect option can be correct as : (yellow) X–Trachea : It serve as a passage of air 5. Basic solutions have pH > 7. So, C represents the highly basic area in the given graph. Y –Bronchiole : It deliver air to the alveoli 6. Reduction W–Larynx : It serves as a chamber for respiratory functions. 3Fe + 4H2O Fe3O4 + 4H2 Oxidation 12. The correct labelling is SAMPLE PAPER 5 The substance which is reduced is H2O because 1-Stomach, 2-Pancreas, 3-Small intestine, after the removal of oxygen atom, it becomes 4-Large intestine, 5-Liver, 6-Mouth H2. Since, H2O gets reduced into H2, it will acts as an oxidising agent also because the Stomach secretes pepsin, salivary glands in substance which gets reduced is also known mouth secretes salivary amylase, pancreas as oxidising agent. secretes trypsin and lipase and small intestine secretes lipase, peptidase, etc. 7. Zinc reacts with dil. HCl and produces zinc chloride and hydrogen gas. 13. In the stem of woody plants, the exchange of Zn + 2 HCl ¾® ZnCl2 + H2 respiratory gases takes place through small pores called lenticels whereas in herbaceous (dil.) plants, stomata found on the stem helps in exchange of respiratory gases. The surface of Zn metal become dull because of reaction with HCl to form zinc chloride.

152 CBSE Sample Paper Science Class X (Term I) 14. Egg white contains only protein and no fat. 21. When the image is sharp, it is at focus; slightly The digestion of proteins occur in stomach and blurred larger image is beyond focus, and proteins are converted into amino acids. So, slightly blurred smaller image is before focus. amino acids will be found leaving the stomach. \\ f3 < f1 < f2 The absorption of amino acids occurs in small intestine. So, only water will be found leaving 22. The correct diagram among the given the small intestine. diagrams of mirror is shown 15. Amoeba takes in food using temporary P FC finger-like extensions of the cell surface which fuse over the food particle forming a 23. To form an erect and magnified image, an food vacoule. object must be placed between the optical centre and focus of given convex lens. 16. The correct labelling is So d should be less than 20 cm. A-Right ventricle As f = 20 cm, hence distance of object from the lens is d < 20 cm. B-Right atrium 24. When a ray of light incident on a refractive C-Left atrium surface, then it emerges out to be parallel with the incident ray but displaced laterally. So, ray D-Left ventricle NQ is the correct emergent ray. The right atrium receives the deoxygenated 25. Pb3O4(s) ¾¾D ® PbO(s) + O2(g) blood from the different body parts. The right ventricle transport deoxygenated blood to the This is an endothermic reaction because to lungs. carry out this reaction, Pb3O4 is heated and oxygen gas is evolved. The left atrium receives the oxygenated blood from lungs which then enter left ventricle and Thus, option (c) is correct. transported to various body parts. 26. Higher the pH value, lower the concentration 17. In foggy weather, light is scattered by the tiny of H+ ions. water droplets present in air. So, the person So, in solution A, the concentration of H+ ions who is travelling in day time in foggy weather is lowest. Hence, the pH value will be higher in is not able to see things clearly because very solution ‘A’. less amount of light is entering into his eyes. 18. When white light passes through a prism, it gets dispersed as shown in the figure below. 27. When ferrous sulphate is heated, it produces ferric oxide and sulphur dioxide and sulphur White Red trioxide gases. ¾¾D ® ¾¾D ® light Violet FeSO4 × 7H2O(s) - 7H2O FeSO 4 ( s) Fe2O3(s) + SO2(g) + SO3(g) Red light is least scattered and hence, it The gases produced are toxic in nature. deviates less than the violet and blue. Hence, to avoid inhaling toxic gases, IV is 19. Only a concave mirror can have a correct position to observe the reaction. magnification greater than one. Hence, the SAMPLE PAPER 5 given mirror is a concave mirror. 28. The decreasing reactivity order of metals is 20. When a convex lens is immersed in a liquid of Al > Zn > Fe > Cu. refractive index greater than the refractive index of glass, then it will act like a diverging From the results given in the table, Al is the lens. most reactive among others because it shows displacement reactions in three solution, Zn Because by the definition, concave lens, is a shows displacement reaction in two solutions rarer medium surrounded by two surfaces of and iron shows displacement in one solution. denser medium. The least reactive metal is copper as it does not react with any solution.

CBSE Sample Paper Science Class X (Term I) 153 29. I, II and III observations are correct. Onion is 38. Statement (c) is incorrect and can be corrected as, an olfactory indicator whose odour changes or vanished in basic medium and remained In humans, the respiratory pigment is unchanged in acidic medium. haemoglobin which has a very high affinity for 30. Zn, being more reactive than iron and copper, oxygen. therefore displaces the iron and copper from their solutions. Hence, Fe and Cu will form 39. Given, power of a corrective lens, P = 1.5 D coating on zinc due to displacement reaction. We know that, power (P) = 1 31. Both A and R are true and R is the correct explanation of A. focal length ( f ) Zinc being more reactive than hydrogen, \\ Focal length, f = 1 = 1 Þ f = 0.67 m displaces it from its solution (i.e. HCl) and P 1.5 form ZnCl2. 40. As refractive index of medium A is smaller 32. A is true but R is false. among others, so it is the rarest medium, hence the speed of light in medium A is fastest. Weak acids have low electrical conductivity Frequency does not change with change in due to partial dissociation in aqueous medium. refractive index. They produce less number of ions. The concentration of H+ ions is more in strong 41. The liquid waste product of plants formed due acids and less in weak acids. to oxidation of various essential oil is resins that protects the plants from insects and 33. Both A and R are true, but R is not the correct pathogens. explanation of A. 42. The undigested food enters the large intestine Translocation of solutes is the movement of from the small intestine where reabsorption of organic food or solute in soluble form from one water occurs. If the undigested food is kept too part to another part of plant. long in our large intestine then the undigested food will become more dry and hard. Translocation of solutes take place across the phloem. Solutes can be translocated both in 43. As, ÐD + ÐA = Ði + Ðe upward and downward directions due to end to end arrangement of sieve tubes. Þ ÐD = Ði + Ðe - ÐA = 40° + 40° - 60° 34. Both A and R are correct and R is the correct [QÐi = Ðe = 40°, ÐA = 60°] explanation of A. The distance above the principal axis is always considered as positive. Þ ÐD = 20° Hence, the height of an object is always positive. 44. In case of normal incidence, Ði = 0 35. The reactions of Zn and Na2CO3 with acids and bases are as follows: \\ Ðr = 0 i.e. there is no refraction and hence, no deviation. Zn + 2 HCl ¾® ZnCl3 + H2 Zn + 2 NaOH ¾® Na2ZnO2 + H2 45. Here, f = - 20 cm and v = - 50 cm Na2CO3 + 2 HCl ¾® 2 NaCl + CO2 + H2O Na2CO3 + NaOH ¾® No reaction The image must be real, inverted and beyond Hence, student I has given the correct set of C. Therefore, the object must lie between F and observation. C, i.e. between 20 cm to 40 cm. 36. The correct sequence for the transportation of 46. The path of ray can be shown as blood from lungs to various body parts is Lungs ® Pulmonary vein ® Left atrium A Various body parts ¬ Aorta ¬ Left ventricle Incident 45º r SAMPLE PAPER 5 37. Pancreas secretes pancreatic juice which ray 45º contains digestive enzymes like lipase and trypsin. Trypsin digests the proteins and lipase 45º breaks down the emulsified fats. BC Here, i = 45° For minimum refractive index, the light should be just totally internally reflected. \\ r = 90°

154 CBSE Sample Paper Science Class X (Term I) Using Snell’s law, Superior vena cava brings deoxygenated blood from upper part of the body, while inferior m sin 45° = sin 90° vena cava bring blood from lower parts of the body into the right atrium of the heart. \\ m= 1 = 2 1 2 55. The blood vessel D (aorta) receives oxygen rich blood from the left ventricle and circulates it to 47. Given, f = 50 cm, u = - 60 cm, different parts of the body. ho = 10 mm = 1 cm 56. The blood vessel C (pulmonary artery) has got deoxygenated blood, while the blood vessel F Using lens formula, (pulmonary vein) has oxygenated blood. 1-1= 1 vu f 57. When the object is moved away from the convex mirror, the image moves closer to the Þ 1= 1+1= 1 - 1 focus till it becomes a point sized image. v f u 50 60 Thus, size of the image decreases with Þ 1=6-5= 1 distance. v 300 300 58. Given, f = + 30 cm, m = 1 Þ v = + 300 cm 4 \\Magnification, m = hi = v Q m = - v = 1 or u = - 4v ho u u4 Þ hi = 300 Using mirror formula, 1 - 60 1 =1+1 f vu Þ hi = - 5 cm Þ 1=1- 1 = 3 48. For making utensils, element should be hard, f v 4v 4v good conductor of heat and lustrous. So, these properties are only present in element C. or v = 3 f = 3 ´ 30 = 22.5 cm and u= - 90 cm 44 49. In test tube A, Fe(s) + CuSO4(aq) ¾® FeSO4(aq) + Cu(s) 59. Convex mirrors are used as rear view mirrors The reaction involved is displacement reaction in cars because they always form virtual and as copper is displaced by iron from its sulphate solution. erect image and provide a wider field of view as they are curved outwards. 50. Fe (s) + CuSO4 (aq ) ¾® FeSO4 (aq) + Cu (s) 60. Given, h1 = 7 cm, u = - 20 cm, f = 30 = 15 cm is the balanced chemical equation as the total 2 number of atoms of each elements are equal on both sides of the equation. Hence, it is a Using mirror formula, balanced reaction with correct physical states 1 =1+1 of the chemicals. f vu 51. As iron is more reactive than copper, copper Þ 1= 1-1 will not displace iron from its sulphate v fu solution and hence, there will be no reaction. Þ 1 = 1 - èæç 1 ø÷ö = 4+3 = 7 v 15 -20 60 60 52. Copper sulphate solution is blue in colour, but SAMPLE PAPER 5 after the displacement reaction take place, the or v = + 60 cm ferrous sulphate solution forms which is light 7 green in colour. \\ Magnification, m = h2 = - v h1 u 53. Interventricular septum separates part A (right - 60 ventricle) and part B (left ventricle). Þ h2 = 7 = 3 54. Right atrium receives blood from superior and 7 -20 7 inferior vena cava. Þ h2 = + 3 cm

SAMPLE PAPER 6 SCIENCE A Highly Simulated Practice Questions Paper for CBSE Class X (Term I) Examination Instructions Maximum Marks : 40 Time allowed : 90 Min. (i) This paper is divided into three Sections: (a) Section A – Contains 24 questions. Attempt any 20 questions. (b) Section B – Contains 24 questions. Attempt any 20 questions. (c) Section C – Contains 12 questions. Attempt any 10 questions. (ii) Each questions carries 0.80 mark. (iii) There is NO negative marking. Roll No. Section A Section-A consists of 24 questions. Attempt any 20 questions from this section. The first attempted 20 questions would be evaluated. 1. A student used the following reaction for the preparation of oxygen gas in laboratory : 2KClO3 (s) ¾H¾e¾at ® 2KCl(s) + 3O2(g) Catalyst What would he observe about the reaction? (a) The reaction is endothermic and a type of decomposition reaction. (b) It is a decomposition reaction and exothermic in nature. (c) It is a photochemical decomposition reaction and exothermic in nature. (d) It is a displacement reaction. 2. Identify the colour change in hydrated copper sulphate crystals in the given experiment. Removing water of crystallisation . (a) Blue to green (b) Blue to white (c) Blue to colourless (d) Blue to black

156 CBSE Sample Paper Science Class X (Term I) 3. Iron Steam Iron (II), (III) oxide Gas Which of the following combination are correct about the acidic nature of oxide of iron and gas? Acidic Gas evolved (a) Yes No (b) No Yes (c) Yes Yes (d) No No 4. Identify the balanced equation from the following. (a) 2K(s) + H2O(l) ¾® KOH(aq) + H2(g) (b) K(s) + 2H2O(l) ¾® KOH(aq) + 2H2(g) (c) 2K(s) + 2H2O(l) ¾® 2KOH(aq) + H2(g) (d) K(s) + H2O(l) ¾® KOH(aq) + H2(g) 5. The graph given below depicts a neutralisation reaction, (HCl + NaOH ¾® NaCl + H 2O). The pH of solution changes as we add excess of acid to an alkali. 14 A B 7 C pH D 0 Volume of acid added Which letter denotes the area of the graph where formation of NaCl observed? (a) A (b) B (c) C (d) D SAMPLE PAPER 6 6. In the reaction of iron with water, 3Fe(s) + 4H 2O(g) ¾® Fe3O4(s) + 4H 2 (g) Which option in the given table correctly represents the substance oxidised and reducing agent? Substance oxidised Reducing agent (a) Fe Fe H2 (b) H2O Fe (c) Fe3O4 H2O (d) H2

CBSE Sample Paper Science Class X (Term I) 157 7. The chemical reaciton between copper oxide and hydrogen can be categorised as : (a) double displacement reaction (b) combination reaction (c) redox reaction (d) exothermic reaction 8. Which of the given option correctly represents the parent acid and parent base of ammonium carbonate? Parent acid Parent base (a) NH3 H2CO3 (b) H2CO3 NH4 OH (c) H2CO3 NH 3 (d) HNO3 Na2CO3 9. How will you identify that the reaction occurs between potassium iodide and lead nitrate solution? (a) By checking its temperature. (b) By formation of white precipitate. (c) By the formation of yellow insoluble precipitate. (d) By stirring. 10. What will be correct statement regarding universal indicator? (a) It is an indicator having pH = 7 (b) It gives orange colour at pH = 3 (c) It gives blue colour at pH = 5 (d) It becomes colourless at pH = 7 11. Carefully study the diagram of the cross-seciton of leaf with label (i), (ii), (iii) and (iv). Select the option which gives correct identification and main function and/or characteristics. Midrib Lamina or leaf blade Veinlet Phloem Xylem (iii) Vascular bundle (iv) (i) Air spaces (ii) Lower SAMPLE PAPER 6 Stomatal pore epidermis (a) (i) Chloroplast – are present in the mesophyll cells of green plants (b) (ii) Guard cells – controls the exchange of gases (c) (iii) Waxy cuticle – helps in photosynthesis (d) (iv) Upper epidermis – It contains millions of stomata and regulate gas exchange

158 CBSE Sample Paper Science Class X (Term I) 12. Identify the option that indicate the parts that carry deoxygenated blood. (iii) (i) (ii) (a) (i) Right atrium, (ii) pulmonary arteries, (iii) Vena cava (b) (i) Right atrium, (ii) Vena cava, (iii) Pulmonary arteries (c) (i) Vena cava, (ii) Pulmonary vein, (iii) Plumonary ateries (d) (i) Right atrium, (ii) vena cava, (iii) Pulmonary veins 13. Which of the following is a protein digesting enzyme? (a) Pepsin (b) Bile (c) Lipase (d) Salivary amylase 14. The figure given below shows a human digestive system with labels (i) to (iv). Identify the correct label with its function. Mouth/Buccal cavity (i) Salivary glands Tongue Liver (ii) Diaphragm Small intestine Gall bladder (iv) (stores bile) Rectum SAMPLE PAPER 6 (iii) Appendix Anus (a) (i) Oesophagus – ensures swift movement of food by way of rhythmic relaxation and contraciton of muscles (b) (ii) Stomach – secretes HCl that helps in emulsification of fats (c) (iii) Pancreas – secretes acidic pancreatic juice containing enzymes (d) (iv) Large intestine – secretes trypsin for the digestion of proteins

CBSE Sample Paper Science Class X (Term I) 159 15. The given diagram represents the process of transpiration taking place in plants. Arrows indicates movement of water during transpiration. Which of the following statement is correct regarding of transpiration : (a) Evaporation of water molecules creates suction which provide water to the roots. (b) Transpiration occurs mainly with the half of xylem present in leaves. (c) Transpiration cause water to rise in plants by pulling it upwards. (d) The effect of root pressure in transport of water is more important during daytime. 16. Observe the diagram of human excretory system. (A) (B) (D) (C) Match the labelling in Column I and correlate with the function in Column II. Column I Column II A 1. It stores urine until it is passed out. B 2. It allows urine to pass outside the body. C 3. It is involved in the formation of urine. D 4. It collects urine from the kidney. Codes SAMPLE PAPER 6 AB C D AB C D (a) 3 1 4 2 (b) 2 3 4 1 (c) 3 4 2 1 (d) 3 4 1 2 17. The depth of a bucket filled with water seems to be less than its actual depth. Which phenomena is responsible for this? (a) Reflection of light by surface of water (b) Scattering of light by water molecules (c) Refraction of light at the interface (d) Dispersion of light by surface water molecules

160 CBSE Sample Paper Science Class X (Term I) 18. Which diagram shows image formation of an object on a screen by a diverging mirror? (a) Object (b) Object F F Object Object (c) (d) FF 19. Both a spherical mirror and a thin spherical lens have a focal length of - 15 cm. What type of mirror and lens they are there? (a) Concave mirror and convex lens (b) Concave mirror and concave lens (c) Convex mirror and convex lens (d) Convex mirror and concave lens 20. If a beam of red light, yellow light and violet light are incident at the same angle on the inclined surface of a prism from air and produce angle of deviation r, y and v respectively, which of the following is correct? (a) r < y < v (b) v < r < y (c) v < y < r (d) y < r < v 21. A concave mirror produces a magnification of +2. The object is placed (a) at focus of mirror (b) between focus and centre of curvature (c) between focus and pole (d) beyond centre of curvature 22. SAMPLE PAPER 6 O Examine the above figure and state which of the following option is correct? [one small box in the figure = 1 cm] (a) The magnification of image is +1 and image is +3 cm from mirror. (b) The magnification of image is -1 and image is -3 cm from mirror (c) The magnification of image is -1 and image is +3 cm from mirror (d) The magnification of image is +1 and image is -3 cm from mirror. 23. Diamond sparkles more than a similar cut glass piece. It is because (a) more cuts are present on diamond than that on glass piece. (b) more internal reflection takes places due to greater refractive index of diamond. (c) dispersion of light is shown by diamond. (d) scattering occurs in diamond.

CBSE Sample Paper Science Class X (Term I) 161 24. Two identical prisms P1 and P2 are used to study the recombination of white light. What is the correct position of prisms, so that a narrow beam of white light incident on one prism (P1) emerges out from the second prism (P2 ) as white light? White White White White light light light light (a) (i) (i) (ii) (iii) (iv) (c) (iii) (b) (ii) (d) (iv) Section B This section consists of 24 multiple choice questions with overall choice to attempt any 20 questions. In case more than desirable number of questions are attempted, ONLY first 20 will be considered for evaluation. 25. Sodium carbonate ¾¾D¾® Na2O + X Identify the correct option from the given table which represents the type of reaction and gas evolved in the reaction. Exothermic Gas evolved (a)   (b)   (c)   (d)   26. In which country is the concentration of hydrogen ion is the highest? pH value O A BC D E Countries (a) A (b) C (c) D (d) E 27. When metal (M) is treated with diluted H 2SO4, then the gas is evolved and is collected over the water as shown in figure. Identify the correct conclusion drawn. (b) The evolved gas is lighter than air. SAMPLE PAPER 6 (a) The gas evolved is hydrogen. (d) Both (a) and (b) (c) The evolved gas is SO2.

162 CBSE Sample Paper Science Class X (Term I) 28. A boy met with an accident and his leg get fractured. He went to the doctor and the doctor mixed a white powder in water and applied it on his leg along with cotton and gauze. Which of the following statement is true about white powder? (I) White powder is Plaster of Paris. (II) On mixing the white powder and water, gypsum is formed. (III) White powder is also used to ornate designs on walls and ceiling. (IV) It gives off CO2 on mixing with water. Choose the correct option. (a) II and III (b) I, II and III (c) III and IV (d) I and IV 29. The table shown below gives information about four metals: A, B, C and D and these metals are treated with water, steam and dil. HCl. The results are given below. Metals Reaction with water Reaction with steam Reaction with dil. HCl A No Yes Yes B No No Yes C Yes Yes Yes D No No No The metal A would be (a) Fe (b) Cu (c) K (d) Ag 30. On mixing aqueous solutions of sodium sulphate and barium chloride, the correct observation is shown in test tube. SAMPLE PAPER 6 ppt ppt Clear solution ppt I II III IV (a) I (b) II (c) III (d) IV Direction (Q. Nos. 31-34) For given questions two statements are given-one labelled Assertion (A) and the other labelled Reason (R). Select the correct answer to these questions from the codes (a), (b), (c) and (d) as given below. (a) Both A and R are true and R is the correct explanation of A. (b) Both A and R are true, but R is not the correct explanation of A. (c) A is true, but R is false. (d) A is false, but R is true. 31. Assertion Iron articles are painted to prevent rusting. Reason Rusting damages the iron articles and form a reddish-brown layer on them. 32. Assertion The bleaching powder is basic in nature. Reason Bleaching powder is used as an oxidising agent in chemical industries. 33. Assertion Lungs always contain a residual volume of air. Reason It is to ensure enough time for the release of CO2 and for the absorption of O2 .

CBSE Sample Paper Science Class X (Term I) 163 34. Assertion The Sun is visible to us about 2 minutes before the actual sunrise and about 2 minutes after the actual sunset. Reason The time difference between actual sunrise and apparent sunrise is about 2 minutes. 35. The table given below shows the colour change of indicator in acidic and basic medium. Which of the following information is incorrect? Indicators Colour change in acid Colour change in base (i) Blue litmus paper  (ii) Turmeric   (iii) Methyl orange   (iv) Phenolphthalein   Choose the correct option. (a) (i) and (ii) (b) (ii) and (iii) (c) (iii) and (iv) (d) (ii) and (iv) 36. Which of the following substances are produced by anaerobic respiration in yeast? (a) Carbon dioxide, lactic acid and water (b) Carbon dioxide and alcohol (c) Lactic acid and water (d) Alcohol and water 37. Which process occurring in human body does not involve energy from respiration? (a) Contraction of heart muscle (b) Diffusion of oxygen from the alveoli into the blood (c) Digestion of bread (d) Maintaining a constant body temperature 38. Which of the following statement is true about respiration? (a) During inhalation, ribs move inward and diaphragm is raised. (b) In the alveoli, exchange of gases takes place, i.e. oxygen from alveolar air diffuses into blood and carbon dioxide from blood into alveolar air. (c) Haemoglobin has greater affinity for carbon dioxide than oxygen. (d) Alveoli increases surface area for exchange of blood. 39. If the angle of refraction is 30°. Find the angle of incidence of light ray incident on surface of a plastic slab of refractive index 3. (a) 30° (b) 60° (c) 90° (d) 45° 40. An object is placed 20 cm in front of a concave mirror of focal length 25 cm. The image of object will be formed at (a) 1 ´ 10 2 cm behind the mirror (b) 1 ´ 10 2 cm in front of mirror (c) 2 ´ 10 2 cm in front of mirror (d) 2 ´ 10 2 cm behind of mirror 41. Which of the following organisms have a parasitic mode of nutrition? SAMPLE PAPER 6 (a) Mushrooms, Cuscuta, bacteria (b) Ticks, lice, yeasts (c) Cuscuta, ticks, tapeworms (d) Amar-bel, leeches, amoeba 42. The function of the lymph fluid is to (a) drains excess fluid from extracellular space back into the blood (b) carries digested and absorbed fat from intestine (c) circulates around the body and help in clotting of blood (d) Both (a) and (b)

164 CBSE Sample Paper Science Class X (Term I) 43. If the power of a lens is -10 D, then it means that the lens is a (a) convex lens of focal length -10 m (b) concave lens of focal length +10 m (c) concave lens of focal length -10 cm (d) convex lens of focal length +10 cm 44. If the real image of a candle flame formed by a converging lens is twice the size of flame and the distance between lens and image is 40 cm. At what distance should the candle be placed from the lens? (a) -20 m (b) 40 cm (c) 80 cm (d) -20 cm 45. Principal 2F1 F1 O F2 2F2 Axis A student tried to find out the image formation of above setup, he concluded the following (I) the image will be formed between focus and optical centre of lens. (II) the image is real. (III) this is a concave lens, hence its focal length is positive. (IV) the size of image is very small. Which one combination of the above statements is correct? (a) (II) and (III) are correct (b) (I) and (IV) are correct (c) (I), (III) and (IV) are correct (d) (I), (II), (III) and (IV) are correct 46. A graph is drawn between sine of angle of incidence and sine of angle of refraction for four colours A, B, C and D. C sin i D A B sin r Which colour have high refractive index? (a) C (b) D (c) A (d) B 47. A¢ SAMPLE PAPER 6 A O F2 B¢ F1 B The above lens has a focal length of 20 cm. The object height is 5 mm which is placed at a distance of 10 cm from optical centre. The magnification of object is (a) 1 (b) -2 (c) 2 (d) -1

CBSE Sample Paper Science Class X (Term I) 165 48. The inspection authority visited the cable manufacturing company. They tested their cable products A, B, C and D, on the basis of their properties. Properties AB C D Malleable Yes No No Yes Ductile Yes No No Yes Electrical conductivity No Yes Yes Yes Melting point High Low Low High Which of the following products were disapproved by them? (a) A, B and C (b) B, C and D (c) B and C (d) C and D Section C This Section C consists of three Cases followed by questions. There are a total of 12 questions in this section. Attempt any 10 questions from this section. The first attempted 10 questions would be evaluated. Case I. To check the reaction of acid with zinc, the experiment is performed with zinc granules, sulphuric acid and soap solution. Some zinc granules are taken in test tube and dilute sulphuric acid is added to it. The appratus is set as shown below. A burning candle is taken near the soap bubbles filled with gas. Stand Delivery Burning of tube gas with a pop sound Test Gas Candle tube bubbles Dilute Soap bubble sulphuric Zinc filled with gas acid granules Soap solution 49. Which gas is produced by the reaction of zinc and dilute sulphuric acid? (a) H2S (b) CO2 (c) O2 (d) H2 50. Which salt is produced in test tube during the experiment? (a) Zinc hydroxide (b) Zinc sulphate SAMPLE PAPER 6 (c) Zinc oxide (d) Zinc carbonate 51. Identify the correct chemical equation involved in this experiment. (a) Zn(s) + 2H2SO4 (aq) ¾® ZnSO4(s) + H2(g) (b) Zn(s) + H2SO4 (aq) ¾® ZnSO4(aq) + H2(g) (c) 2Zn(s) + 2H2SO4 (aq) ¾® 2 ZnSO4(aq) + H2(g) (d) 2Zn(s) + 2H2SO4 (aq) ¾® 2ZnSO4(s) + H2(g)

166 CBSE Sample Paper Science Class X (Term I) 52. What is the role of soap solution in this experiment? (a) It changes the acidity of gas evolved. (b) It is used for fragrance. (c) It provides medium for bubble formation in which H2 is trapped in small parts (d) All of the above Case II. Rahul was undergoing the treatment for kidney failure. This process is managed by artificial kidney. It is the process in which nitrogenous wastes are removed from the blood through dialysis. It contains the number of tubes with a semipermeable lining suspended in a tank filled with a dialysing fluid. Tubing made up of X a selectively permeable membrane Line from Dialysing apparatus solution to vein Fresh dialysing Y solution 53. The above diagram represents the process of haemodialysis, which is done to remove (a) extra blood (b) extra cellular fluid (c) extra urea (d) extra water 54. Normally in a healthy adult, daily initial filtrate in the kidneys is about (a) 180 L (b) 150 L (c) 100 L (d) 250 L 55. Which substance have the lowest concentration at X and the highest concentration at Y ? (a) Glucose concentration is lowest at X and salts concentration is highest at Y. (b) Urea concentration is lowest at X and salts and urea concentration is highest at Y. (c) Water concentration is highest at X and glucose concentration is lowest at Y. (d) Water concentration is lowest at X and glucose concentration is highest at Y. SAMPLE PAPER 6 56. Which of the following statements are incorrect for dialysis ? I. The fluid has same osmotic pressure as blood except that it is devoid of nitrogenous waste. II. The waste products from the blood pass into dialysing fluid by osmosis. III. This process is different because there is more reabsorption involved. IV. The actual volume of initial filtrate excreted is only a litre or two a day. Choose the correct option. (b) II and III (d) Only II (a) I and II (c) II, III and IV

CBSE Sample Paper Science Class X (Term I) 167 Case III. Priyanka observed the apparent random wavering or flickering of objects when seen through a turbulent steam of hot air rising above a fire or a radiator. She noticed that the air just above the fire becomes hotter than the air further up. She wants to know about this phenomenon. She listed some similar phenomena based on this effect and tried to know more. Observes eye Water Burner 57. Which phenomena is observed by Priyanka when she saw through a steam of hot air? (a) Scattering of light (b) Atmospheric refraction (c) Tyndall effect (d) Absorption of light 58. She listed some phenomena similar to this, choose the correct one which are present on the list. (a) Twinkling of stars, advance sunrise and delayed sunset. (b) Tyndall effect and scattering of light. (c) Colour of sun at sunrise and sunset. (d) Formation of rainbow and dispersion. 59. Her friend is trying to observe the star in sky and concluded the following (i) The position of stars changes continuously. (ii) Light comes to earth after reflection from earth’s atmosphere. (iii) Due to dispersion, different colours of stars are seen from earth. (iv) Light suffers refraction from different layers of atmosphere. Which combination is correct for given statements? (a) (i) and (ii) (b) (iii) and (iv) (c) (i) and (iv) (d) (ii) and (iv) 60. Colder layers of air present in atmosphere are considered as SAMPLE PAPER 6 (a) optically rarer medium (b) optically opaque medium (c) crystalline medium (d) optically denser medium

OMR SHEET SP 6 Roll No. Sub Code. Student Name Instructions Use black or blue ball point pens and avoid Gel & Fountain pens for filling the OMR sheet. Darken the bubbles completely. Don’t put a tick mark or a cross mark, half-filled or over-filled bubbles will not be read by the software.  Correct Incorrect Incorrect Incorrect Do not write anything on the OMR Sheet. Multiple markings are invalid. 1 21 41 2 22 42 3 23 43 4 24 44 5 25 45 6 26 46 7 27 47 8 28 48 9 29 49 10 30 50 11 31 51 12 32 52 13 33 53 14 34 54 15 35 55 16 36 56 17 37 57 18 38 58 19 39 59 20 40 60 Check Your Performance Score Percentage = Total Correct Questions 100 Total Questions: × Total Correct Questions: Total Questions Less than 60% > Average (Revise the concepts again) If Your Score is Greater than 60% but less than 75% > Good (Do more practice) Above 75% > Excellent (Keep it on)

CBSE Sample Paper Science Class X (Term I) 169 Answers 1. (a) 2. (b) 3. (b) 4. (c) 5. (c) 6. (a) 7. (c) 8. (b) 9. (c) 10. (b) 11. (a) 12. (b) 13. (a) 14. (a) 15. (c) 16. (d) 17. (c) 18. (c) 19. (b) 20. (a) 21. (c) 22. (a) 23. (b) 24. (d) 25. (b) 26. (b) 27. (d) 28. (b) 29. (a) 30. (c) 31. (a) 32. (b) 33. (a) 34. (b) 35. (c) 36. (b) 37. (b) 38. (b) 39. (b) 40. (a) 41. (c) 42. (d) 43. (c) 44. (d) 45. (b) 46. (a) 47. (c) 48. (a) 49. (d) 50. (b) 51. (b) 52. (c) 53. (c) 54. (a) 55. (b) 56. (b) 57. (b) 58. (a) 59. (c) 60. (d) EXPLANATIONS 1. 2KClO3(s) ¾¾He¾at ® 2KCl(s) + 3O2(g) 6. In the given reaction, 3Fe(s) + 4H2O(g) ¾® Fe3O4 (s) + 4H2(g) Catalyst Fe is oxidised by gaining oxygen atoms and hence, it acts as a reducing agent because the The reaction is endothermic in nature as KClO3 substance which gets oxidised is called absorbs heat to form KCl and O2. The reaction reducing agent. in which single reactant breaks down to form two or more products is known as 7. The reaction between copper oxide and decomposition reaction. It is a type of hydrogen take place as follows: decomposition reaction as KClO3 breaks down to produce two products i.e. KCl and O2. Reduction 2. The chemical formula of hydrated copper CuO(s) + H2(g) ¾® Cu(s) + H2O(l) sulphate is CuSO4 × 5H2O. Oxidation On heating, water of crystallisation is removed which leads to formation of CuSO4 that is This reaction is a redox reaction because white in colour. oxidation and reduction occurs simultaneously. CuSO4 × 5H2O ¾H¾eat® CuSO4 8. H2CO3 + NH4OH ¾¾® (NH4 )2 CO3 (Blue) (White) Ammonium The blue colour of hydrated copper sulphate is Carbonic acid Ammonium carbonate due to presence of water of crystallistion which changes into white due to removal of water of (Parent acid) hydroxide crystallisation by heating. (Parent base) 3. Fe(s) + H2O(g) ¾® Fe2O3(s) + H2(g) Ammonium carbonate is formed by the reaction between carbonic acid (parent acid) and ammonium hydroxide (parent base). According to this reaction, when iron reacts 9. The reaction between potassium iodide and with steam of water, oxide of iron is formed lead nitrate solution forms yellow insoluble along with hydrogen gas. precipitate of lead iodide. By observing yellow precipitate, one can identify the completion of The iron oxide is basic in nature because iron is reaction. metal and metallic oxide are basic in nature and non-metal oxides are acidic in nature. 10. Universal indicators are used to judge how strong or weak a given acid or base. It is a 4. Chemical equation shown in option (c) is mixture of several indicators. It shows SAMPLE PAPER 6 balanced one. different coloures at different concentrations of hydrogen ions in a solution. It gives shade of 2K(s) + 2H2O(l) ¾® 2KOH(aq) + H2(g) red in acidic range i.e. 1-6 and shade of blue in A balanced chemical equation is one in which basic range is 8-14. the total number of atoms of each element are equal on both sides of the equation. Hence, option (b) is correct which says that universal indicator gives orange colour at 5. NaCl is a salt which is neutral in nature and pH = 3 (acidic medium). the pH of neutral substances is equal to 7. Hence, C is the letter which denotes the area 11. Chloroplast are the site of photosynthesis as where formation of neutral salt (NaCl) take they contain chlorophyll pigment. These are place. the organelles present in the mesophyll cells of green plants.

170 CBSE Sample Paper Science Class X (Term I) 12. (i)-Right atrium, (ii)-Vena cava, (iii)-Pulmonary 22. As the image is formed by a plane mirror so arteries. the magnification is +1. In figure, it is clear that object is – 3 cm away from the mirror, so the These parts carry deoxygenated blood. Vena image will be + 3 cm away from the mirror. cava carries deoxygenated blood from all body parts to the right atrium. 23. Refractive index of diamond is more than that of glass. As the light enters through the surface Pulmonary arteries carry deoxygenated blood of diamond, it suffers total internal reflection from right ventricle to the lungs. and traps in it. That’s why diamond sparkles more than glass. 13. Pepsin is a protein digesting enzymes present in the stomach. It breaks down the larger 24. The correct position of prism P1 and P2 to get polypeptide into smaller peptide fragments. white light after recombination is shown below. 14. Oesophagus is a tube that carries food from White light your mouth to your stomach. It ensures the White light swift movement of food by the way of rhythmic relaxations and contractions of muscles. White White light light 15. The loss of water in the form of vapours from Screen the aerial parts of the plants is called Screen transpiration. Evaporation of water molecules from leaf’s cells creates a suction (transpiration 25. Na2CO3(s) ¾He¾ate®d Na2O(s) + CO2(g) pull) which pulls water from the xylem cells of This reaction is endothermic as sodium the roots. carbonate absorbs heat to from Na2O and CO2. In this reaction, carbon dioxide gas is evolved. 16. The correct labelling is Hence, option (b) is correct. A-Kidney B-Ureter 26. As we know, lower the pH value, higher the concentration of H+ ions. The bar graph of C-Urinary bladder D-Urethra country C shows least value of pH. Hence, the concentration of hydrogen ions is the highest Kidneys are the main excretory organ in in country C. humans. It is involved in the formation of urine. These wastes are removed from blood 27. Metal + Acid ¾® Salt + H2 by kidneys and are passed down to the urinary So, when metal reacts with dil. H2SO4 , it will bladder by a pair of ureters. The urethra produce salt and hydrogen gas. The hydrogen further releases the urine out of the body. gas is lighter than air. 17. Due to refraction of light at interface of water 28. The white powder that is used by doctors to and air, light bends and the depth of a bucket filled with water seems to be less than its treat fractured bone is called as plaster of Paris. actual depth. On mixing with water, plaster of Paris changes 18. The image formation of an object on a screen by a diverging mirror is shown below. to gypsum to give hard solid mass. CaSO4 × 1 H2O + 11 H2O ¾® CaSO4 × 2H2O 2 2 Plaster of Paris Gypsum A A¢ This plaster of Paris is also used to ornate object designs on walls and ceiling. image B B¢ F Hence, statement I, II and III are correct SAMPLE PAPER 6 The image formed by convex mirror is always whereas statement (IV) is incorrect as it does vitrual and diminished. not give off carbon dioxide (CO2) on mixing 19. Both concave mirror and concave lens have with water as shown in given reaction. negative focal length. 29. The metal A would be iron (Fe) as it does not 20. Red light deviates least and violet light deviates react with water (hot or cold), but reacts with most. So, the angle of deviation of red (r), yellow steam. Iron also reacts with dil HCl. (y) and violet (v) are in order of r < y < v. Reaction with steam 21. As magnification is greater than 1. So, the object is placed between pole and focus of 3Fe + 4H2O ¾® Fe3O4 + 4H2 concave mirror to produce enlarged image. (Iron) (Steam) (Ferrous oxide) (Hydrogen) Reaction of Fe with dil. HCl Fe + 2HCl ¾® FeCl2 + H2 ­ (Iron) (dil.) (Ferrous chloride) (Hydrogen)

CBSE Sample Paper Science Class X (Term I) 171 30. When barium chloride combines with sodium Pyruvate ¾In ¾abs¾en¾ce o¾f O®2 Ethanol + CO2+ Energy sulphate in aqueous solution, then white precipitate of barium sulphate is formed which (in yeast) is insoluble in water. So, III test tube shows correct observation. 37. Diffusion of oxygen from the alveoli into the Na2SO4 + BaCl2 ¾¾® BaSO4 ¯ +2 NaCl blood does not require energy from respiration because diffusion is a passive process and do (white ppt) not need energy to occur. 31. A and R are both true and R is the correct 38. In the alveoli, exchange of gases takes place, explanation of A. i.e. oxygen from alveolar air diffuses into blood and carbon dioxide from blood into alveolar The phenomenon due to which metals are air. slowly eaten by the reaction of air, water and chemicals present in the atmosphere is called Other statements are incorrect and can be corrosion. Corrosion of iron is known as corrected as rusting of iron. It damages the articles of iron, therefore to prevent rusting of iron, paints are (a) During inhalation, ribs lift up and applied on iron materials. diaphgram flattens to increase the size of chest cavity. 32. A and R are true, but R is not correct explanation of A. (c) Haemoglobin present in RBCs has a very high affinity for oxygen. Bleaching powder is basic in nature because it reacts with acid and forms salt and water. (d) Alveoli increases the surface area for exchange of gases. 33. Both A and R are true and R is the correct explanation of A. 39. Given, m = 3, r = 30°, i = ? During the breathing cycle, when air is taken Using Snell’s law, in and let out, the lungs always contain a m = sin i residual volume of air so that there is suficient sin r time for oxygen to be absorbed and for the carbon dioxide to be released. \\ 3 = sin i sin 30° 34. Both A and R are correct, but R is not the correct explanation of A. Þ sin i = 3 2 When the Sun is slightly below the horizon, its light coming from less dense to more dense air, or i = sin-1 æ 3 ö = 60° is refracted downwards. Because of this, the ç ÷ Sun appears to be raised above the horizon è 2ø and so, the rising Sun can be seen about 2 minutes before actual sunrise. Similarly, due to 40. Given, u = - 20 cm, f = - 25 cm atmospheric refraction the Sun can be seen for about 2 min even after the actual sunset. Using mirror formula, SAMPLE PAPER 6 1 =1+1 The time difference between actual sunrise and f uv apparent sunrise is about 2 minutes. Þ 1= 1-1= 1 - 1 35. The colour change shown by methyl orange v f u (-25) (-20) and phenolphthalein are correctly shown in = -4+5 = 1 the table. Whereas correct colour change of 100 100 blue litmus and turmeric is as follows Þ v = 100 cm (i) Blue litmus turns red in acidic medium = 1 ´ 102 cm and show no change in basic medium. Here, v is positive. So, image is formed behind (ii) Turmeric remains same (yellow) in the mirror. acidic medium, but becomes red in basic medium. 41. Some organisms derive nutrition from plants or animals without killing them. This parasitic 36. Anaerobic respiration takes place in absence of nutritive strategy is used by a variety of oxygen. During anaerobic respiration in yeast organisms like Cuscuta (amar-bel), ticks, lice, cells, pyruvate breakdown to produce ethanol leeches and tapeworms. (alcohol), carbon dioxide and energy. 42. Lymph is a colourless fluid that contains white blood cells. It drains into the streams via lymphatic system.

172 CBSE Sample Paper Science Class X (Term I) Lymph carries digested and absorbed fat 49. Hydrogen gas is evolved, when zinc reacts with from intestine and drains excess fluid from dil.sulphuric acid. extracellular space back into the blood. Zn(s) + dil.H2SO4 ¾® ZnSO4(aq) + H2(g) 43. Given, 50. Zinc sulphate is produced during the reaction Power, P = - 10 D P = 100 between Zn and dil. H2SO4 . f (in cm) Zn(s) + H2SO4 (aq) ¾® ZnSO4 (aq) + H2 Þ -10 = 100 Zinc Dil. sulphuric acid f Zincsulphate Hydrogen or f = - 10 cm 51. The correct chemical equation involved in the experiment is Concave lens has negative focal length. Zn(s) + H2SO4 (aq) ¾® ZnSO4(aq) + H2(g) 44. Given, m = - 2, v = 40 cm 52. Soap solution provides the medium for H2 gas to Magnification, m = v Þ u= v= 40 get trapped in small parts and determined its u m -2 presence by taking a burning candle near the soap bubbles filled with hydrogen gas. or u = -20 cm 53. Haemodialysis or artificial kidney is a device to 45. The object is placed at finite distance, so the remove nitrogenous waste products (urea) from image will formed between focus and optical the blood. This procedure is used to treat both centre and on the same side of lens as object. temporary and permanent kidney failure. The image is small in size, virtual and erect. The focal length of concave lens is always 54. Normally in a healthy adult, the initial filtrate in negative. the kidneys is about 180 L daily. However, the volume actually excreted is only one or two litre 46. The slope of sin i versus sin r graph a day, because the remaining filtrate is reabsorbed in the kidney tubules. represents refractive index of medium i.e., m = sin i 55. Urea from blood has diffused into dialysis fluid in the dialysis. sin r Hence, the blood returning to the body (X) has a so, the slope of colour C is more, hence its low concentration of urea and liquid (Y ) has the refractive index is highest among rest of the highest concentration of salts and urea. colours. 56. Statement II and III are incorrect and can be 47. Given, f = 20 cm corrected as ho = 5 mm = 0.5 cm, u = - 10 cm II. The waste products from the blood pass into By lens formula, dialysing fluid by diffusion. 1-1= 1 III. This process is similar to the function of the vu f kidney, but it is different since there is no reabsorption involved. 1- 1 = 1 v (-10) 20 57. Due to atmospheric refraction, wavering and flickering of objects is seen through a turbulent 1 = 1 - 1 Þ v = - 20 cm steam of hot air. v 20 10 58. The phenomena caused due to atmospheric Magnification, m= v = - 20 = 2 refraction are twinkling of stars at night, advance u - 10 sunrise and delayed sunset. SAMPLE PAPER 6 48. To be approved by inspection authority, 59. When light comes from stars to the observer, it cables should be malleable (can be beaten suffers from atmospheric refraction due to into thin sheets), ductile (can be drawn into different layers of earth’s atmosphere. The thin wires), good conductor of electricity and position of stars also seems to be changing have high melting point. continuously. All these properties are present in cable D 60. Molecules are closely packed in low temperature, only. Therefore, the product A, B and C were so the colder layers of air present in atmosphere disapproved as cable material as they do not are considered as optically denser medium. have all these properties.

SAMPLE PAPER 7 SCIENCE A Highly Simulated Practice Questions Paper for CBSE Class X (Term I) Examination Instructions Maximum Marks : 40 Time allowed : 90 Min. (i) This paper is divided into three Sections: (a) Section A – Contains 24 questions. Attempt any 20 questions. (b) Section B – Contains 24 questions. Attempt any 20 questions. (c) Section C – Contains 12 questions. Attempt any 10 questions. (ii) Each questions carries 0.80 mark. (iii) There is NO negative marking. Roll No. Section A Section-A consists of 24 questions. Attempt any 20 questions from this section. The first attempted 20 questions would be evaluated. 1. Choose the correct observation when aluminium strip is kept in freshly prepared ferrous sulphate solution in a test tube. (a) Light green colour solution changes to colourless solution (b) A colourless gas smells like burning sulphur is observed (c) Green colour of solution slowly turns brown (d) The test tube becomes slightly hot 2. A student adds few drops of the universal indicator to a solution of dilute hydrochloric acid in the way shown here. Drops of universal indicator Hydochloric acid Identify the colour change of dil. HCl solution. (a) Green (b) Red (c) Blue (d) Colourless

174 CBSE Sample Paper Science Class X (Term I) 3. Metal Cold water Metal hydroxide Gas Which of the following two combinations are correct ? Metal Gas evolved (i) Cu No (ii) Na No (iii) Ca Yes (iv) Fe Yes Codes (a) (i) and (ii) (b) (ii) and (iii) (c) (i) and (iii) (d) (iii) and (iv) 4. Which of the following correctly represents a balanced chemical equation? (a) C2H6 + 4O2 ¾® 2 CO2 + 2 H2O (b) 2 C2H6 + 5O2 ¾® 4CO2 + 5H2O (c) 2 C2H6 + 7O2 ¾® 4CO2 + 6H2O (d) C2H6 + 6O2 ¾® CO 2 + 6H2O 5. A few drops of lemon juice is added to milk to make curd. After a few hours, the milk turns into curd. The given graph is plot by observing the given situation. pH value O Time What does the graph indicates? (a) The acidity of milk increases with time (b) The pH value of milk becomes high with time (c) The basicity of milk increases with time (d) All of the above 6. In the reaction of manganese dioxide with hydrochloric acid, MnO 2 (s) + 4HCl(aq) ¾® MnCl 2 (aq) + 2H2O(l) + Cl2 (g) Which option in the given table correctly represents the substance reduced and the oxidising agent? SAMPLE PAPER 7 Option Substance reduced Oxidising agent (a) MnO2 MnO 2 (b) HCl MnCl 2 (c) MnCl2 Cl 2 (d) H2O H2O

CBSE Sample Paper Science Class X (Term I) 175 7. The chemical reaction between potassium iodide and lead nitrate can be classified as (a) decomposition reaction (b) double displacement reaction (c) displacement reaction (d) redox reaction. 8. Which of the given option correctly represents the parent acid and parent base of magnesium nitrate? Parent acid Parent base (a) MgCl 2 NaOH (b) H 2CO 3 (c) HNO 3 Mg 3N 2 (d) HNO 3 MgCl 2 Mg(OH) 2 9. When electricity is passed through an aqueous solution of NaCl, then (a) chlorine gas is given off at the anode (b) sodium hydroxide solution is formed near the cathode (c) hydrogen gases is given off at the cathode (d) All of the above 10. Which of the following statement is true about the action of sodium carbonate on litmus paper? (a) The red litmus turns blue (b) The blue litmus turns red (c) No change on litmus (d) First blue colour appears, then it becomes colourless 11. Carefully study the diagram of the human circulatory system with labels (i), (ii), (iii) and (iv). Select the option which gives correct identification and main function and/or characteristic. (i) (iii) Right side of heart Left side of heart (iv) (ii) (a) (i) Pulmonary Artery – Thick walled and carry blood from body to lungs. SAMPLE PAPER 7 (b) (ii) Capillary – One cells thick and helps in exchange of gases. (c) (iii) Pulmonary veins – Thick walled and carry blood from lungs to various body parts. (d) (iv) Aorta – Thin walled and carry deoxygenated blood to the lung capillaries.

176 CBSE Sample Paper Science Class X (Term I) 12. Identify the option that indicates correct material digested in the location (i), (ii) and (iii). (i) (ii) SAMPLE PAPER 7 (iii) (a) (i)-Starch, (ii)-Fats, (iii)-Proteins (b) (i)-Proteins, (ii)-Carbohydrates, (iii)-Starch (c) (i)-Starch, (ii)-Proteins, (iii)-Proteins (d) (i)-Fats, (ii)-Proteins, (iii)-Fats 13. What is the correct sequence of air during exhalation? (a) Alveoli ® Bronchus ® Bronchioles ® Trachea ® Nostrils (b) Nostrils ® Pharynx ® Larynx ® Trachea ® Alveoli (c) Alveoli ® Trachea ® Pharynx ® Larynx ® Nostrils (d) Alveoli ® Trachea ® Larynx ® Pharynx ® Nostrils 14. The figure given below shows a structure of nephron with labels (i) to (iv). Identify the correct label with its functions. (ii) (iii) (i) (iv) (a) (i) Renal artery – Takes impure blood to the kidneys (b) (ii) Bowman’s capsule – Collects the blood from tubules (c) (iv) Collecting duct – Dilution of urine (d) (iii) Tubular part of nephron – Reabsorbs salts and major amount of water of nephron

CBSE Sample Paper Science Class X (Term I) 177 15. Identify the correct statement about the process of haemodialysis represented by the diagram given below. Arrow indicates the flow of dialysing solution. Line from Tubing made up of artery to pump a selectively permeable membrane Line from Dialysing apparatus solution to vein Fresh dialysing Used dialysing solution solution (with urea and excess salts) (a) During this passage, the waste products from blood pass into dialysing fluid by faciliated diffusion. (b) During the process, reabsorption of salts and minerals occurs. (c) The patient’s blood pass through the tubes having impermeable lining. (d) The fresh dialysing solution is entering the patient’s body and impure dialysing solution is coming out of the body simultaneously. 16. Observe the flow chart of breakdown of glucose by various pathways. Glucose B Ethanol + Carbon dioxide + Energy (6-carbon molecule) A Pyruvate C Lactic acid + Energy (3-carbon D Carbon dioxide + Water + Energy molecule + Energy) Match the labelling referred in Column I and correlate with the Column II. Column I Column II A 1. This process takes place in the mitochondria. B 2. It occurs when there is lack of oxygen in muscles. C 3. This process takes place in yeast during fermentation. D 4. It is first step in the break down of glucose into pyruvate. SAMPLE PAPER 7 Codes ABCD ABCD (a) 4 3 2 1 (b) 4 1 3 2 (c) 4 2 1 3 (d) 4 3 1 2 17. When light falls on a smooth polished surface, then most of the light is (a) reflected in same direction (b) refracted in different directions (c) refracted into the second medium (d) scattered away

178 CBSE Sample Paper Science Class X (Term I) 18. Four students A, B, C and D carried out measurement of focal length of a concave mirror as shown in the four diagrams. AB CD The best result will be obtained by which student ? (a) Student A (b) Student B (c) Student C (d) Student D 19. In a glass prism, the emergent ray is not parallel to the incident ray because (a) the laws of reflection do not hold in case of glass prism. (b) the refracting surfaces are inclined at an angle. (c) the angle of refraction in glass is greater than the angle of incidence. (d) the angle of refraction in glass is greater than the angle of emergence. 20. Consider these two indices of refraction; flint glass: 1.52 and diamond: 2.42. Based on the refractive indices of these materials, choose the correct option. (a) The speed of light in diamond > the speed of light in flint glass. (b) The speed of light in flint glass is equal to the speed of light in diamond. (c) The speed of light in flint glass > the speed of light in diamond. (d) The speed of light is independent of the refractive index of material. 21. M1 i M2 SAMPLE PAPER 7 Examine the above diagram and choose which of the following is correct? (a) The angle of incidence should be 30° for parallel rays. (b) The angle of reflection is greater than angle of incidence in this case (c) If the angle between M1 and M2 is less than 90°, then the rays will become parallel (d) If M1 and M2 are inclined at 90°, then the incident and reflected rays will be parallel. 22. AM CF P

CBSE Sample Paper Science Class X (Term I) 179 A ray of light AM is incident on a concave mirror as shown. Then which of the following ray diagrams is correct for the reflected ray? A F M A F M (a) P (b) P C C A F M A F M (c) P P (d) C C 23. mw mg In the given figure, path of a parallel beam of light passing through a convex lens of refractive index m g kept in a medium of refractive index m w , which of the following is correct? (a) m g > mw (b) m g = m w (c) m g < m w (d) m g = 1 mw 24. The minute particles and molecules of the atmosphere deflect the sunlight in all directions. Which of the following phenomenon is involved here? (a) Dispersion (b) Scattering (c) Refraction (d) Tyndall effect Section B Section B consists of 24 questions (Sl. No. 25 to 48). Attempt any 20 questions from this section. The first attempted 20 questions would be evaluated. 25. Sodium hydrogen carbonate ¾¾® Na 2 CO 3 + X + H2O D Identify the correct option from the given table which represents the type of reactions and gas evolved. Exothermic Gas evolved (a) ü 7 (b) 7 ü (c) ü ü (d) 7 7 SAMPLE PAPER 7 26. A boy recorded a pH value of soil sample (A), rain water sample (B), tap water sample (C) and vinegar (D). He plotted the pH value of the four samples in the given graph. 7 pH value A BCD

180 CBSE Sample Paper Science Class X (Term I) Which of the following sample has highest concentration of hydrogen ion? (a) Soil sample (b) Tap water sample (c) Rain water sample (d) Vinegar 27. The diagram shows the reaction between dil. H 2 SO 4 and five different metals, magnesium, zinc, aluminium, iron and copper. 15 mL of dilute sulphuric acid is added to each of them. Identify the incorrect statement. (a) The rate of evolution of hydrogen gas bubbles is not same in each test tube (b) The rate of formation of bubbles is the fastest in the case of magnesium (c) No bubbles are seen in case of copper (d) The reactivity order of these metals in Mg > Zn > Fe > Al > Cu 28. The electronic configuration of six elements A to F are given in the table below. Electronic configuration Formula of compounds (i) A : 2, 1 B : 2, 6 A2B (ii) B : 2, 6 C : 2, 5 B2C3 (iii) C : 2, 5 D : 2, 2 C2D3 (iv) E : 2, 8, 5 F : 2, 8, 8, 2 EF 3 Which of the following compound has wrong formula? (a) (i) and (ii) (b) (ii) and (ii) (c) (iii) and (iv) (d) (ii) and (iv) 29. A student took a blue litmus paper and dipped it in dil. H 2 SO 4 and then in dil. NaOH solution. He observed that (i) the colour of litmus paper changes to red. (ii) the colour of litmus paper first changes to red and then to blue. (iii) the colour of litmus paper changes from blue to colourless. (iv) the colour of litmus paper shows different colours in different mediums. Which of the following observations is true? (a) (i) and (ii) (b) (ii) and (iv) (c) (iii) and (iv) (d) (i) and (iii) SAMPLE PAPER 7 30. In four test tubes, there are different sample. On addition of phenolphthalein, the test tube II and III shows pink colour and I and IV shows no change. Moreover, red cabbage water is added to each sample. The test tube IV shows purple colour, I shows red and II and III shows blue colour. I II III IV

CBSE Sample Paper Science Class X (Term I) 181 Which of the following test tubes contain sample with pH < 7? (a) I and IV (b) II and III (c) Only I (d) Only II Direction (Q. No. 31 to 34) Consist of two statements – Assertion (A) and Reason (R). Answer these questions selecting the appropriate option given below : (a) Both A and R are true and R is the correct explanation of A. (b) Both A and R are true, but R is not the correct explanation of A. (c) A is true, but R is false. (d) A is false, but R is true. 31. Assertion MnO 2 + 4HCl ¾® MnCl2 + Cl 2 + 2H 2 O is a redox reaction. Reason In a redox reaction, oxidation and reduction take place simultaneously. 32. Assertion Aluminium chloride is a basic salt. Reason Aluminium chloride is a salt of strong acid and a weak base. 33. Assertion In a healthy adult, the initial filtrate in the kidneys is about 180 L daily, but the actual volume excreted is only a litre a day. Reason Most of the filtrate is lost from the body in the form of sweat. 34. Assertion It is impossible to see a virtual image with naked eyes. Reason The rays do not actually emanate from a virtual image. 35. The table given below shows the reaction of a few elements with acids and base to evolve hydrogen gas. Elements Acid Base M ü ü N 77 O ü7 P üü Which of the following elements can form amphoteric oxides? (a) M and N (b) N and O (c) M and P (d) N, M and P 36. In which of the following vertebrate group /groups, heart does not pump oxygenated blood to different parts of the body? SAMPLE PAPER 7 (a) Pisces and amphibians (b) Amphibians and reptiles (c) Amphibians only (d) Pisces only 37. During photosynthesis, which of the following event takes place? (a) Oxidation of CO 2 into carbohydrates (b) Reduction of carbohydrates into CO 2 (c) Reduction of CO 2 into carbohydrates (d) Oxidation of carbohydrates into CO 2

182 CBSE Sample Paper Science Class X (Term I) 38. The excretory system of human being consists of (a) a kidney, a ureter, a urinary bladder and a urethra. (b) a pair of kidneys, a ureter, a pair of urinary bladders and a urethra (c) a pair of kidneys, a pair of ureters, a urinary bladder and a urethra (d) a kidney, a pair of ureters, a urinary bladder and a urethra 39. One-half of a convex lens is covered with a black paper. The size of image produced will be (a) half the size of object (b) same as that of object (c) two-third the size of object (d) one-fourth the size of object 40. Two lenses of focal length 20 cm and -10 cm are combined as shown. The combination of these will become (a) converging lens with focal length 20 cm (b) diverging lens with focal length -10 cm (c) converging lens with focal length -20 cm (d) diverging lens with focal length 10 cm 41. Enzyme trypsin and pepsin works in (a) basic and acidic medium, respectively (b) acidic and basic medium, respectively (c) acidic medium only (d) neutral medium only 42. The force that blood exerts against the wall of vessels is (a) more in veins and less in arteries (b) more in arteries and less in veins (c) more in capillaries (d) more in both veins and arteries 43. An object of size 7 cm is placed at 27 cm in front of a concave mirror of focal length 18 cm. At what distance from the mirror should be placed, so that a sharp focused image can be obtained? (a) 27 cm (b) 54 cm (c) -27 cm (d) -54 cm 44. Incident light 45° Air Incident light 45° Air SAMPLE PAPER 7 Medium Medium 30° P 20° Q Air Air For the same angle of incidence of 45°, the refraction angle in two transparent media P and Q is 30° and 20° , respectively. Which one of the following is correct? (a) Medium P is the denser medium than medium Q (b) Speed of light in both media is same. (c) Medium Q is the denser medium than medium P (d) Angle of emergence for both media are greater than incidence angle.

CBSE Sample Paper Science Class X (Term I) 183 45. O F 20 cm The focal length of above mirror is 10 cm, the image will formed (a) at 20 cm behind the mirror (b) at focus of mirror (c) between mirror and focus (d) at the centre of curvature of mirror 46. A convex lens has focal length 30 cm. If an object is placed at a distance of 15 cm from it, then the magnification produced by the lens is (a) 6 (b) 2 (c) 1 (d) 0.5 47. A beam of light when passes through a glass prism, a spectrum is observed. But when same beam is passed through a hollow glass prism, then (a) same spectrum is obtained (b) spectrum becomes brighter (c) spectrum gets reversed (d) no spectrum is observed 48. Element Ductile Melting point Electrical conductivity A Yes High Yes B Yes High No C No Low No D Yes Low Yes Which of the above elements can be used for making wires? (a) A, B (b) B, C (c) A, D (d) Only A Section C SAMPLE PAPER 7 This Section-C consists of three Cases followed by questions. There are a total of 12 questions in this section. Attempt any 10 questions from this section. The first attempted 10 questions would be evaluated. Case I. The samples of sodium chloride, potassium iodide, barium chloride or any other salt are taken from the science laboratory. A small amount of a sample is taken on a metal spatula and heated directly on the flame as shown in figure given below : Spatula containing sample Burner Heating a salt sample on a spatula

184 CBSE Sample Paper Science Class X (Term I) A circuit as shown in Fig. is used to test the electrical conductivity of the given salt solution. Battery Bulb –+ Switch Beaker Graphite rod Salt solution under test 49. The physical state and properties of the salt samples used in the given activity is (a) all are crystalline solids (b) all are brittle (c) all are having high melting point (d) All of the above 50. Choose the correct observation when the salt sample is taken on a metal spatula and heated directly on the flame (a) the salt undergo sublimation (b) the salts melt immediately (c) the salts given out characteristics flame upon heating (d) the salts do not melt easily 51. Which of the following compounds will not conduct electricity in aqueous solution? (a) NaCl (b) CCl 4 (c) CaCl 2 (d) KCl 52. A student noted the following observations with four compounds P, Q, R and S. Compound Melting point (K) Boiling point (K) P 1074 1686 Q 250 350 R 290 391 S 2850 3120 Which of the following compounds are ionic in nature? SAMPLE PAPER 7 (a) P and Q (b) Q and R (c) R and S (d) P and S

CBSE Sample Paper Science Class X (Term I) 185 Case II. Amoeba is a single celled organism. It ingest food with the help of ‘X’. These form the food vacuole over the food particle. In food vacuole, the complex food is broken down into smaller molecules which then diffuse into the cytoplasm. The remaining undigested food is expelled out by the process ‘Y ’. B (i) X C (ii) A (iii) (iv) Y (b) food particle, nucleus and food vacuole (d) food particle, nucleus and pseudopodia 53. In diagram labelled A, B and C indicates (a) food particle, food vacuole and nucleus (c) food vacuole, nucleus and food particle 54. The labelled part Y represents which stage of nutrition? (a) Ingestion (b) Digestion (c) Egestion (d) Absorption 55. The characteristics of labelled part X is (a) it is small hair-like structures present on Amoeba body (b) it is finger-like projections on cell surface (c) it is tube-like structures coming out of the body (d) it is suckers which is attached to the wall of the intestine 56. Which of the following is true for the process of nutrition in Amoeba? (i) The food is taken in by the entire surface (ii) The pseudopodias are the permanent structures on cell surface of amoeba (iii) The cell membrane ruptures and eliminates out undigested food. (iv) Within the vacuole, egestion of food occurs. (a) (i) and (iii) (b) (i) only (c) (i) and (ii) (d) (ii) and (iv) Case III. A student suggested the following guidelines to his friend for doing the experiment on SAMPLE PAPER 7 tracing the path of a ray of light on passing through a rectangular glass slab, for three different angles of incidence i PQ r r S eR A. Draw the outline of the glass slab at three positions on the drawing sheet. B. Draw normals on the top side of these outlines near their right end. C. Draw the incident rays on the three outlines in directions making angles of 30°, 45° and 60° with normals drawn.

186 CBSE Sample Paper Science Class X (Term I) D. Fix two pins vertically on each of these incident rays at two points exactly 1 cm apart. E. Look for the images of the feet of these pins while fixing two pins, from the other side, to get the refracted ray. 57. When he showed these guidelines to his teacher, the teacher told him that two of them need to be corrected and modified. These two guidelines are (a) B and C (b) C and D (c) D and E (d) B and D 58. How may refractions of light ray occur on passing through a glass slab? (a) One (b) Two (c) Three (d) Four 59. He performs the experiment for two different values of angle of incidence : Ði = 30° and Ði = 45°. The set of values of the angle of refraction (Ðr) and angle of emergence (Ðe), he is likely to observe in the two cases, are (a) [Ðr = 30° , Ðe = 20°] and [Ðr = 45° , Ðe = 28°] (b) [Ðr = 20°, Ðe = 30°] and [Ðr = 45°, Ðe = 28° ] (c) [Ðr = 20°, Ðe = 30°] and [Ðr = 28°, Ðe = 45°] (d) [Ðr = 30°, Ðe = 20°] and [Ðr = 28°, Ðe = 45°] 60. He noted some observations from this demonstration, choose the correct one. (a) Ði is more than Ðr but (nearly) equal to Ðe (b) Ði is less than Ðr but (nearly) equal to Ðe (c) Ði is more than Ðe but (nearly) equal to Ðr (d) Ði is less than Ðe but (nearly) equal to Ðr SAMPLE PAPER 7

OMR SHEET SP 7 Roll No. Sub Code. Student Name Instructions Use black or blue ball point pens and avoid Gel & Fountain pens for filling the OMR sheet. Darken the bubbles completely. Don’t put a tick mark or a cross mark, half-filled or over-filled bubbles will not be read by the software.  Correct Incorrect Incorrect Incorrect Do not write anything on the OMR Sheet. Multiple markings are invalid. 1 21 41 2 22 42 3 23 43 4 24 44 5 25 45 6 26 46 7 27 47 8 28 48 9 29 49 10 30 50 11 31 51 12 32 52 13 33 53 14 34 54 15 35 55 16 36 56 17 37 57 18 38 58 19 39 59 20 40 60 Check Your Performance Score Percentage = Total Correct Questions 100 Total Questions: × Total Correct Questions: Total Questions Less than 60% > Average (Revise the concepts again) If Your Score is Greater than 60% but less than 75% > Good (Do more practice) Above 75% > Excellent (Keep it on)

188 CBSE Sample Paper Science Class X (Term I) Answers 1. (c) 2. (b) 3. (c) 4. (c) 5. (a) 6. (a) 7. (b) 8. (d) 9. (d) 10. (a) 11. (b) 12. (c) 13. (d) 14. (d) 15. (a) 16. (a) 17. (a) 18. (a) 19. (b) 20. (c) 21. (d) 22. (c) 23. (b) 24. (b) 25. (b) 26. (d) 27. (d) 28. (d) 29. (b) 30. (c) 31. (a) 32. (d) 33. (c) 34. (d) 35. (c) 36. (d) 37. (c) 38. (c) 39. (b) 40. (a) 41. (a) 42. (b) 43. (d) 44. (c) 45. (d) 46. (b) 47. (d) 48. (d) 49. (d) 50. (d) 51. (b) 52. (d) 53. (b) 54. (c) 55. (b) 56. (a) 57. (d) 58. (b) 59. (c) 60. (a) EXPLANATIONS 1. The freshly prepared ferrous sulphate solution 6. MnO2 is getting reduced to MnCl2 by removal was green in colour before placing aluminium strip in it. Then the colour of solution changes of oxygen atoms. So, MnO2 acts as an to brown slowly because the displacement oxidising agent also because the substance reaction takes place as Al is more reactive than which is getting reduced is called oxidising Fe, according to reactivity series. agent. FeSO4(aq) + Al(s) ¾® Al2(SO4 )3(aq) + Fe 7. The reactions in which two compounds (Brown ) exchange their ions to form two new compounds (Green) are called double displacement reactions. 2. The student would observed that the colour of Hence, the given chemical reaction is a type of acid changes to red after the addition of double displacement reaction. universal indicator. This shows that hydrochloric acid is a strong acid with an 2KI(aq) + Pb(NO)3(aq) ¾® approximate pH of 2. Potassium iodide Lead 2KNO3(aq) + PbI2(s) nitrate 3. (i) Copper does not react with cold water and Potassium Lead iodide hence, no gas evolved. nitrate (ii) Sodium reacts violently with cold water. 8. Magnesium nitrate is formed by the reaction 2Na + 2H2O ¾® 2NaOH + H2 + Heat between nitric acid (parent acid) and Therefore, hydrogen gas is evolved. magnesium hydroxide (parent base). (iii) Calcium reacts with cold water and forms Mg(OH)2(s) + 2HNO3(aq) ¾® Mg(NO3 )2(aq) + 2H2O(l) Ca(OH)2 and hydrogen gas. 9. All of the given statements are correct. Ca(s) + 2H2O(l) ¾® Ca(OH)2(aq) + H2(g) Electric Calcium Cold Calcium Hydrogen 2NaCl(aq) + 2H2O(l) current 2NaOH(aq) water hydroxide (iv) Fe does not react with water at all. Thus, Sodium Water Sodium no gas is evolved. chloride hydroxide Hence, option (c) is correct. + Cl2(g) + H2(g) Chlorine Hydrogen SAMPLE PAPER 7 4. 2C2H6+ 7O2 ¾® 4CO2+ 6 H2O is a balanced When electricity is passed through an aqueous solution of sodium chloride, it decomposes to equation as in this reaction, total no. of form sodium hydroxide near the cathode, elements in all the elements are balanced or chlorine gas is given off at the anode and equal in both sides of the equation. 5. The milk is almost neutral and its pH range is hydrogen gas at the cathode. around 6-7. This process is called chlor-alkali process. On addition of lemon juice, which is acidic in 2NaCl(aq) + 2H2O(l) Electric 2NaOH(aq) nature, increase the acidity of milk and with current time, milk turns into curd. This decreases Sodium Water (Sodium hydroxide) the pH of milk which is then converted into curd. chloride + Cl2(g) + H2(g) Chlorine Hydrogen

CBSE Sample Paper Science Class X (Term I) 189 10. The red litmus turns blue on the action of tank filled with dialysis fluid. During the SAMPLE PAPER 7 sodium carbonate because sodium carbonate procedure of dialysis, patient’s blood is passed is derived from a weak acid and a strong base. through these tubes. As the blood passes, the Thus, sodium carbonate is basic in nature. waste products from the blood moves into dialysing fluid by diffusion and the purified 11. (ii) Capillaries are the smallest vessels and blood is pumped back into the patient’s body. have one-cell thick walls. Exchange of material between the blood and 16. In all cases, the first step is breakdown of surrounding cells takes place across this glucose (6-C molecule) into pyruvate (3-C thin wall. molecule). This process occur in the cytoplasm (A). Further, the pyruvate may be converted The incorrect options can be corrected as into ethanol and carbon dioxide. This process takes place in yeast (B) during fermentation. (i) Pulmonary artery–Thick-walled and carries blood from heart to lungs. Breakdown of pyruvate using oxygen takes place in the mitochondria (D). This process (iii) Pulmonary veins–Thin-walled and carry breaks up pyruvate into carbon dioxide and blood from lungs to heart. water. In the lack of oxygen in the muscle cells (C), the pyruvate is converted into lactic acid. (iv) Aorta–Thick-walled and carries oxygenated blood from left ventricle to 17. When light falls on a smooth polished surface, other body parts. most of it is reflected in the same direction, this is known as regular reflection. 12. (i) Mouth is the first part of the digestive system from where the food enters into the 18. Student A will obtain the best result for correct alimentary canal. In mouth, digestion of measurement of focal length, sharp image starch occur with the help of salivary must be obtained on the screen and the amylase enzyme. meterscale must be correctly placed between screen and centre of concave mirror. (ii) In stomach, protein is digested by the enzyme pepsin. 19. As the two reflecting surfaces of prism are not parallel to each other. (iii) In small intestine, digestion of carbohydrates, protein and fats occur. So, these surfaces are inclined to each other at an angle called angle of prism and the angle of 13. In order for the lungs to expel air, the refraction is always less than the angle of diaphragm relaxes which pushes up the lungs. incidence and the angle of emergence in the Then the air flows from alveoli to the trachea denser medium. Therefore, the emergent ray is then through the larynx and pharynx to the not parallel to the incident ray. nasal cavity where it is expelled out of the body via nostrils. 20. Given, m g = 1.52 , md = 2.42 14. The labelled part are as follows Speed of light in medium µ1 (i) Renal artery Refractive index of medium (ii) Bowman’s capsule (iii) Tubular part of nephron \\ vg > vd (iv) Collecting duct 21. When two plane mirrors are placed at 90° to (iv) The blood from the Bowman’s capsule each other, then the incident and reflected ray passes through the tubular part of nephron will always be parallel to each other, whatever where useful substances such as glucose, may be the angle of incidence. amino acids, salts and major amount of water are selectively reabsorbed. The incorrect 22. The correct reflected ray is shown as options can be corrected as : A F M (i) Renal artery – Takes pure blood to the C P kidneys. Because light rays incident parallel to the (ii) Bowman’s capsule – Collects filtrate from principal axis goes through focus after the glomerulus and returns it to the tubules. reflection. (iv) Collecting duct – Concentration of urine. 15. Artificial kidney is a device used to remove nitrogenous waste products from the blood through dialysis. It contains number of tubes with a semipermeable lining suspended in a

190 CBSE Sample Paper Science Class X (Term I) 23. The beam of light doesn’t deviate at any point (iv) E : 2, 8, 5 and F : 2, 8, 8, 2 on passing through lens, which means the \\The valency of E and F are 3 and 2 material of lens and medium is same. Hence, respectively. mg = mw EF 24. Scattering is the phenomenon in which minute particles and molecules present in air deflect 32 the sunlight in all directions. E2 F3 25. When sodium hydrogen carbonate is heated, The formula of (iv) is E2F3 and not EF3. the given reaction take place, Hence, option (d) is correct. NaHCO3 ¾D® Na2CO3 + CO2 + H2O 29. Both (ii) and (iv) are true. Heat is required to proceed this reaction. Hence, the reaction is endothermic in nature The litmus paper shows different colours in and CO2 gas is evolved. different mediums. In acidic medium it changes from blue to red and in basic medium, 26. According to graph, D has lowest pH value it changes red litmus to blue. which means vinegar has lowest pH but highest H+concentration because pH is 30. Phenolphthalein turns colourless in acidic indirectly proportional to concentration of H+ solution and red cabbage juice gives red colour ions. i.e. lower the pH value, higher is the in acidic medium. So, I is acidic in nature and concentration of H+ ions. have pH< 7. 27. Option (d) is incorrect because the correct 31. Both A and R are true and R is the correct reactivity order of the given metals is explanation of A. Mg > Al > Zn > Fe > Cu, according to reactivity series. Reduction 28. (i) A : 2, 1 MnO2 + 4HCl Cl2 + 2H2O + MnCl2 B : 2, 6 Oxidation \\The valency of A and B are 1 and 2 respectively SAMPLE PAPER 7 It is a redox reaction, in which MnO2 gets AB reduced into MnCl2 and HCl get oxidised into H2O, simultaneously. 12 A2B 32. A is false but R is true. Hence, the formula of compound is correct. Aluminium chloride is acidic salt as it is formed by the reaction between weak base and (ii) B : 2, 6 hydrochloric acid (strong acid). C : 2, 5 Al(OH)3 + 3HCl ¾® AlCl3 + 3H2O \\ The valency of B and C are 2 and 3 33. A is true, but R is false. respectively. BC In a healthy adult, the initial filtrate in the kidneys is about 180 L daily, but the actual 23 volume excreted is only a litre a day. Most of B3C2 the filterate is passed through urine. Hence, the formula of (ii) is B3C2 and not 34. A is false but R is true. B2 C3. (iii) C : 2, 5 Virtual image can be seen with naked eyes but D : 2, 2 it cannot be obtained on screen. The rays \\ The valency of C and D are 3 and 2 forming virtual image are appeared to meet respectively. each other. CD 35. Amphoteric oxides are those oxides which can show both acidic and basic behaviour, 32 M and P elements reacts with both acid and C2D3 bases and hence, they can form amphoteric oxides. Hence, the formula of compound is correct.

CBSE Sample Paper Science Class X (Term I) 191 36. Fishes (pisces) have only two-chambered heart Angle of emergence for both the media is same and the blood is pumped to gills for that of angle of incidence because the ray oxygenation and passes directly to the rest of emerges out is parallel to incident ray. the body. 45. Given, u = -20 cm and f = - 10 cm 37. Photosynthesis is a process in which autotrophs such as green plants use carbon Using mirror formula, 1 + 1 = 1 dioxide and water in presence of sunlight to vu f synthesis food. In this, CO 2 is reduced to glucose and water is oxidised to release oxygen. 1=- 1 + 1 v 10 20 38. Human excretory system consists of a pair of Þ v = - 20 cm kidneys, a pair of ureters, a urinary bladder and a urethra. So, the image will be formed at centre of curvature. 39. When a lens is half covered by black paper, then the brightness of image is decreased but 46. Given, f = 30 cm, u = -15 cm full image is obtained on the screen. From lens formula, 40. Given, f1 = - 20 cm, f2 = 10 cm 1-1= 1 Þ 1= 1+1 Total focal length, f is 1 = 1 + 1 f f1 f2 vu f v fu = 1 +1 -20 10 Þ 1= f +u Þ v= fu v fu f +u Þ f = 20 cm \\ m= v = f é fu ù The combination of these two lenses will act as u f +u êQv = ú converging lens of focal length 20 cm. ë f + uû 41. Trypsin works in the basic medium and pepsin = 30 = 30 = +2 works in the acidic medium to digest the 30 - 15 15 proteins in intestine and in stomach, respectively. 47. A hollow prism does not show dispersion of light. Because all colours travel with same 42. The arteries, carry the oxygenated blood from speed in air. So, no spectrum is obtained in the heart to different body parts, while the hollow prism. veins carry the deoxygenated blood from the different body parts back to the heart. 48. For making wires, elements should be ductile, electrical conductor and have high melting Since, the blood emerges from the heart under point. These, properties are present in A high pressure. So, the force that blood exerts element only. against the wall of a vessels is more in arteries and less in veins. 49. All the salts are ionic compounds. They are hard crystalline solids having high melting 43. Given, u = - 27 cm, f = - 18 cm point due to the strong forces of attraction between the positive and negative ions. By mirror formula, 1 + 1 = 1 They are also brittle. Hence, option (d) is vu f correct. Þ 1 = - 1 + 1 = -1 50. The given salts are ionic compounds which v 18 27 54 have very high melting and boiling points as a large amount of energy is required to break the Þ v = - 54 cm strong inter-ionic attraction. 44. As the angle of refraction in medium Q is 51. CCl4 is covalent in nature. Hence, it will not SAMPLE PAPER 7 conduct electricity. Ionic compounds are good smaller than medium P. So, medium Q is the conductors of electricity. denser medium than medium P. Speed of light depends on the refractive index of medium. 52. The melting point and the boiling point of Hence, speed of light in medium P is greater ionic compound is high, hence, P and S are than speed of light in medium Q. ionic compound.

192 CBSE Sample Paper Science Class X (Term I) 53. The labels A, B and C indicates food particle, 57. Normals should be drawn on the top side of nucleus and food vacuole, respectively. the outlines near their left end not right end. The two pins to be fixed vertically on incident 54. The labelled part Y represents process of rays must be suitable distance apart not egestion. 1 cm apart. 55. The labelled X is pseudopodia, which is So, the guidelines B and D need to be temporary finger-like projections on the cell wall corrected and modified. which helps in ingestion of the food. 58. Two refractions occur on passing through a 56. Statement (i) and (iii) are true for the Amoeba. glass slab, one at upper interface of air and The food is taken in by the entire surface. glass and other at lower interface of glass and The remaining undigested food material is air. removed by the cell membrane, which ruptures suddenly at any places and eliminates out the 59. The angle of refraction must be less than undigested food, i.e. egestion. angle of incidence and angle of emergence The incorrect statements can be corrected as i.e., Ðr<30°, also Ð r< 45°. G The pseudopodias are the temporary structures The angle of emergence is always equal to on the cell surface of amoeba. angle of incidence i.e., Ð i = Ð e. G Within the vacuole, complex substances are 60. Angle of incidence is always equal to angle of emergence and angle of refraction is less broken down into simpler ones which then than angle of incidence for glass slab. diffuse into the cytoplasm. SAMPLE PAPER 7

SAMPLE PAPER 8 SCIENCE A Highly Simulated Practice Questions Paper for CBSE Class X (Term I) Examination Instructions Maximum Marks : 40 Time allowed : 90 Min. (i) This paper is divided into three Sections: (a) Section A – Contains 24 questions. Attempt any 20 questions. (b) Section B – Contains 24 questions. Attempt any 20 questions. (c) Section C – Contains 12 questions. Attempt any 10 questions. (ii) Each questions carries 0.80 mark. (iii) There is NO negative marking. Roll No. Section A Section-A consists of 24 questions. Attempt any 20 questions from this section. The first attempted 20 questions would be evaluated. 1. Heena took 5 mL of copper sulphate solution in a beaker and added 3 mL of ammonium hydroxide solution to it. What would she observe? (a) Brown precipitate (b) Pale blue precipitate (c) White precipitate (d) Green precipitate 2. Identify the pH range for vinegar in the given pH scale. Red Yellow Green Blue 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 (a) 0-2 (b) 3-6 (c) 7-10 (d) 11-14 3. Metal Dil. HNO3 Metal salt Gas Which of the following two combinations are correct?