Arihant Science Class 10 Term 1 Sample Paper

94 CBSE Sample Paper Science Class X (Term I) 55. Which of the following statements shows the correct observation for test tube-1 and test tube-2. (a) Test tube - 1 – No change observed and test tube - 2 – Limewater turns milky immediately (b) Test tube -1 – Limewater turns milky immediately and test tube - 2 – No change observed (c) Test tube -1 –Limewater turns milky immediately and test tube - 2 – Limewater turned milky after a long time (d) Test tube -1 –Limewater turns milky after a long time and test tube- 2 – Limewater turns milky immediately 56. Which of the following conclusion is true about the given experiment? (i) Pichkari has more amount of CO 2 than our mouth (ii) Lime water turns milky due to the presence of oxygen (iii) The air exhaled through mouth turns limewater milky at very fast rate (iv) Exhaled air contains more CO 2 as compared to atmospheric air Choose the correct option. (a) (i) and (ii) (b) (iii) and (iv) (c) (ii) and (iii) (d) (i) and (iv) Case III. A student wants to know that what type of image, a spherical mirror forms. So, he placed object at different locations in front of mirror and observed the images. Some images were real, some were virtual. At a specific location, image and object size were same, while at other distances, it is either enlarged or diminished. After understanding this, he observed that this phenomenon is known as reflection of light by spherical surfaces. Hollow sphere of glass Principal C Pole C Principal axis axis Reflecting surface 57. When he placed concave mirror in the experiment, then the image formed of object placed at centre of curvature will be (a) larger than the object (b) smaller than the object (c) highly enlarged but inverted (d) same size as that of object. 58. A convex mirror has wider field of view. Which of the following is correct about it? (a) The image formed is much smaller than the object (b) A large number of images can be seen (c) The image formed is much closer to the mirror (d) All of the above SAMPLE PAPER 2 59. A child standing in front of a magic mirror, finds her head of same size, middle portion smaller and legs bigger than original. Which of the following is the correct sequence of mirrors from the top? (a) Plane, convex and concave (b) Convex, concave and plane (c) Concave, plane and convex (d) Convex, plane and concave 60. To get an image larger than that of object one can use (a) convex mirror but not a concave mirror (b) concave mirror but not a convex mirror (c) Either a convex mirror or a concave mirror (d) a plane mirror

OMR SHEET SP 2 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)

96 CBSE Sample Paper Science Class X (Term I) Answers 1. (a) 2. (a) 3. (c) 4. (c) 5. (d) 6. (b) 7. (c) 8. (d) 9. (a) 10. (a) 11. (b) 12. (a) 13. (b) 14. (d) 15. (d) 16. (a) 17. (c) 18. (d) 19. (d) 20. (a) 21. (b) 22. (b) 23. (a) 24. (c) 25. (c) 26. (c) 27. (b) 28. (b) 29. (b) 30. (d) 31. (a) 32. (c) 33. (d) 34. (c) 35. (d) 36. (b) 37. (d) 38. (c) 39. (d) 40. (c) 41. (d) 42. (d) 43. (b) 44. (b) 45. (a) 46. (a) 47. (a) 48. (b) 49. (a) 50. (c) 51. (b) 52. (c) 53. (b) 54. (c) 55. (d) 56. (b) 57. (d) 58. (d) 59. (a) 60. (b) EXPLANATIONS 1. When lead nitrate is heated, then it 5. The pH value of base is above 7. So, on addition of base to an acid, neutralisation decomposes to form yellow coloured lead reaction take place. oxide, brown coloured fumes of nitrogen dixoide and oxygen. Acid + Base ® Salt + Water 2Pb(NO3 )2(s) ¾¾D ® 2PbO(s) On addition of excess base, the pH of solution rises above 7 due to presence of base along Lead nitrate Lead oxide (Residue) with salt. Hence, D is the correct letter which represents both base and salt. (Yellow) + 4NO2(g) + O2(g) 6. The substance which gets oxidised is called Nitrogen Oxygen reducing agent. So, H2 is oxidised into H2O by dioxide addition of oxygen atom and hence, H2 is also (Brown) the reducing agent. 2. When potassium nitrate is heated, then colourless gas is evolved i.e. oxygen and potassium nitrite formed as product. 7. The reaction which are accompanied by the KNO3 ¾D® KNO2 + O2(g) evolution of heat is called exothermic reaction. Potassium Potassium Oxygen When methane is reacted with oxygen, then nitrate nitrite carbon dioxide and water are formed with 3. The correct combination is (ii) and (iv) as : evolution of heat. Hence, this reaction is (i) When Al reacts with NaOH, then salt of exothermic in nature. aluminium is formed with evolution of hydrogen gas. CH4 + 2O2 ¾® CO2 + 2H2O + Heat Methane Oxygen Carbon Water dioxide 2Al(s) + 6NaOH(aq) ® 2Na3AlO3 + 3H2 ­ 8. Ammonium chloride is formed by reaction between hydrochloric acid (parent acid) and (ii) When silver and sodium hydroxide reacted ammonium hydroxide (parent base) together, then no reaction takes place. Hence. No evolution of gas. HCl + NH4OH ¾® NH4Cl + H2O (iii) Magnesium and sodium hydroxide do not Hydrochloric Ammonium Ammonium Water react with each other. Hence, no evolution acid of gas. hydroxide chloride SAMPLE PAPER 2 (iv) When zinc is reacted with sodium 9. When CO2 gas is passed through limewater, it hydroxide, then zinc salt is formed with turns lime water milky due to formation of evolution of hydrogen gas. calcium carbonate. But, if CO2 is passed in Zn(s) + 2 NaOH(aq) ¾® Na2ZnO2 + H2 ­ excess through lime solution, this milkiness Hence, (ii) and (iv) are correct combination. disappears due to formation of calcium 4. Na2CO3(s) + 2HCl(aq) ¾® 2NaCl(aq) + hydrogen carbonate which is colourless. H2O(l)+ CO2(g) Ca(OH)2(aq) + CO2(g) ® CaCO3(s) + H2O(l) is balance equation because total number of atoms of all the elements are equal on both Limewater Carbon Calcium Water sides of an equation. dioxide carbonate (White) CaCO3(s) + H2O(l) + CO2(g) ¾® Calcium Excess Ca(HCO3 )2(aq) Carbonate (Calcium hydrogen carbonate) (Colourless)

CBSE Sample Paper Science Class X (Term I) 97 10. Bleaching powder (CaOCl2) reacts with carbon flows into tubules by blood capillaries called dioxide present in atmosphere and produce glomerulus. The blood passes through the tubular part of nephron, where important calcium carbonate and chlorine gas, that’s why substances such as glucose, amino acids and a major amount of water are selectively it gives smell of chlorine. reabsorbed by it. The collecting duct finally gathers all the materials that has not returned CaOCl2 + CO2 ¾® CaCO3 + Cl2 to the blood through the tubular membranes. Bleaching Carbon Calcium Chlorine Powder dioxide Carbonate gas 11. The diaphragm helps in the inspiration and 17. When a ray of light falls on the optical centre expiration of air in and out of the lungs. of a lens, then after refraction, it passes undeviated. During expiration, the diaphragm relaxes and returns to its previous shape and then the air is 18. As violet, indigo and blue colours are scattered pushed out of the lungs. most by Earth’s atmosphere because of their shorter wavelength. So, the sunlight becomes The incorrect option can be corrected as yellowish as it is deficient in violet, indigo and blue colours. (i) Trachea It is supported by incomplete cartilage rings. (iii) Ribs When we breathe out, ribs move 19. Refractive index of a medium, downwards. (iv) Awedi Structure in lungs that facilitate m = sin i gaseous exchange. sin r 12. The stomach lining secrete gastric juices and Since, slope angle (q) of given graph > 45° enzymes to digest carbohydrates and proteins. So, food P and Q has carbohydrates and So, refractive index (m) < 1 æ = 1 ö proteins in them, therefore, they both would be çèQ m ÷ partly digested in the stomach. slopeø 13. Rings of cartilage are present in the throat to \\The light is travelling from denser to rarer ensure that the air passage does not collapse. medium and speed of light in medium I is less than the speed of light in medium II. 14. Inside the food vacuole, complex food breaks 20. Given, u = - f down into small molecules and get readily absorbed by the cytoplasm. The undigested 2 food material is removed by the cell membrane, which ruptures suddenly at any Using lens formula, place and eliminates out the undigested food, i.e. egestion. 1=1+ 1 vu f 15. When we breathe in, then Þ 1= 1 + 1 v -f f (i) the muscles between the ribs contracts 2 causing the ribcage to move upward and outward, and = -2 + 1 = - 1 ff (ii) the diaphragm contracts and moves downward. The upward and outward or v = - f movement of ribcage, as well as downward movement of diaphragm, both 21. The path of light on entering the glass prism is increase the space in the chest cavity and shown below make it larger. SAMPLE PAPER 2 16. The correct labelling is Incident ray Emergent A = Bowman’s capsule ray B = Tubular part of nephron C = Glomerulus D = Collecting duct Nephrons has a cup-like capsule called Here, both the incident ray and emergent ray Bowman’s capsule, at its upper end and the bend towards the base of the glass prism at lower end is tube-like and called tubule. Blood both the faces.

98 CBSE Sample Paper Science Class X (Term I) 22. The path of light is shown below : In test tube (C), nitric oxide is evolved. Incident ray 3Cu + 8HNO3 ¾® 3Cu(NO3 )2 + 2NO + 4H2O 40º (Copper) (Dil. nitric (Copper nitrate) (Nitric (Water) oxide) oxide) Refracted In test tube (D), nitric oxide is evolved. ray 40° 3Mg + 8HNO3 ¾® 3Mg(NO3 )2 Emergent (Magnesium) (Dil. nitric (Magnesium ray Glass of window pane oxide) nitrate) + 2NO + 4H2O In glass slab incident angle is equal to (Nitric (Water) emergent angle. Hence, emergent ray is oxide) parallel to incident ray. Hence, only option (b) is incorrect. 23. Concave mirror produces virtual and enlarged image only when the object is placed between 28. In (I), the electronic configuration of A is 2 , 1 pole and focus. So, the distance of tooth from the mirror should be less than 2.5 cm than the and B is 2, 6. focal length. \\ The valency of A is 1 and B is 2. 24. The image is formation of given figure as AB shown below 12 The formula of compound is A2B. In II, the electronic configuration of B is 2,6 and C is 2,7. \\ The valency of B is 2 and C is 1. BC 2f2 f1 O f1 2f2 Image will be formed at focus on the same side 21 of lens as object. It is virtual, erect and highly diminished. The correct formula of compound is BC2. In (III), the electronic configuration of C is 2,7 25. The oxidation of glucose is exothermic process and D is 2, 8, 3. because, it involves evolution of heat. \\ The valency of C is 1 and D is 3. C6H12O6 + O2 ¾¾® CO2 + H2O CD Glucose (Oxygen) (Carbon dioxide) (Water) 13 + Heat ¾® H2CO3 The formula of compound is C3D. (Carbonic acid) In (IV), the electronic configuration of E is 2, 8, 6 and F is 2, 8, 8, 2. H2CO3 is a weak acid and it is called carbonic acid. Hence, option (c) is correct. The valency of E and F is 2 and 2 respectively. EF SAMPLE PAPER 2 26. In the given graph, the pH value touched 22 lowest in 2016 and highest in 2020. However, higher the pH value, lesser is the concentration The correct formula of compound is EF. of H+ ions. Hence, highest concentration of H+ ions is present in 2016, whereas pH value is the Hence, (II) and (IV) are wrongly formed. lowest. 29. Among the given statements related to NaCl, 27. In test tube (A), nitrous oxide is evolved. only (I) statement is wrong, because sodium hydroxide (NaOH) is prepared by chlor-alkali Zn + 4HNO3 ¾® Zn(NO3 )2 + 2N 2O + 2H2O process, but not NaCl salt. (Zinc) (Dil. nitric (Zinc nitrate) (Nitrous Water 30. In test tube A, the solution has pH = 2 (acidic). Hence, on adding universal indicator, it shows acid) oxide) red colour which is correct. In test tube B, the solution has pH = 10 (basic). Hence, on adding In test tube (B), nitric oxide is evolved. universal indicator, it should show dark blue colour instead of green colour. 3Ag + 4HNO3 ¾® 3AgNO3 + NO + 2H2O (Silver) (Dil. nitric (Silver nitrate) (Nitric Water oxide) acid)

CBSE Sample Paper Science Class X (Term I) 99 In test tube C, the solution has pH = 9 (basic). 37. The germinating seed undergo aerobic SAMPLE PAPER 2 Hence, on adding universal indicator, it shows respiration as oxygen is available. blue colour which is correct. In test tube D, the The reaction is solution has pH = 7 (neutral). Hence, on C6H12O6 + 6 O2 ¾® 6 CO2 + 6H2O + energy. adding universal indicator, it should show green colour instead of violet colour. 38. Trypsin is an enzyme that catalyses the digestion of proteins in the small intestine. 31. Both A and R are correct and R is the correct So, if trypsin is lacking in the pancreatic juices, explanation of A. Plaster of Paris is used for the digestion of proteins in the small intestine setting fractured bones because when plaster will not takes place properly. of paris is mixed with water, it forms hard material, known as gypsum, which is used and 39. Given, object distance, u = - 25 cm applied around the fractured limbs. Focal length, f = - 25 cm 32. A is true but R is false because refrigeration of cooked food at low temperature is done to From lens formula, prevent the growth of microorganisms, activity of enzymes and purely chemical reactions. 1 -1 =1 vu f 33. A is false, but R is true. Þ 1= 1 + 1 All the veins carry deoxygenated blood from v -25 (-25) various organs to the heart except pulmonary veins, which carry oxygenated blood from the Þ 1=- 2 lungs to the heart. v 25 34. A is true but R is false. Þ v = - 25 = - 12.5 cm 2 In diffused reflection, a parallel beam of incident light is reflected in different Nature of image is virtual, erect and directions. The laws of reflection are valid at diminished. each and every point of surface either it is smooth or rough. The diffused reflection is due 40. Given, power of convex lens, P1 = 8 D to the roughness of surface. Power of concave lens, P2 = - 10 D 35. (d) In (I) reaction, Na2CO3 reacts with HCl and \\Power of combination, P = P1 + P2 evolves CO2 gas. Na2CO3 + HCl ¾® NaCl + H2O + CO2 = 8 D + (-10 D) In (II) reaction, ZnO reacts with HCl Þ P= -2D but does not evolve CO2 gas. 41. The three main proteolytic enzymes produced ZnO + HCl ¾® ZnCl2 + H2O naturally in your digestive system are pepsin, trypsin and chymotrypsin. In (III) reaction, KOH does not reacts with HCl Pepsin is a stomach enzyme that aids in the and does not evolveCO2 gas, which is incorrect. digestion of protein in food. It breaks down the protein in food into polypeptides. The possible reaction of KOH and HCl is : The pancreas secretes pancreatic juice which contains enzymes like trypsin for digesting KOH + HCl ¾® KCl + H2O proteins. Chymotrypsin plays a significant role in This reaction does not evolve CO2 breakdown of partially hydrolysed proteins into peptides when activated. In (IV) reaction, AgNO3 reacts with HCl but does not evolve CO2. 42. The main function of loop of Henle is absorption of water. Therefore, if Henle’s loop AgNO3 + HCl ¾® AgCl + HNO3 was absent from mammalian nephron, the urine will be more dilute. Hence, option (d) is correct. 43. Given, refractive index of dense flint glass, 36. Bile does not contain any enzyme, instead it m g = 1.65 has bile salts. Bile emulsifies fat into smaller Refractive index of alcohol, ma = 1.36 droplet. Saliva has salivary amylase enzyme, gastric juice has pepsin enzyme and pancreatic juice has trypsin, amylase and lipase enzymes.

100 CBSE Sample Paper Science Class X (Term I) Now, refractive index of dense flint glass w.r.t. ÐD = Ði + Ðe - ÐA alcohol is So, angle of deviation and angle of prism is not amg =mg = 1.65 = 1.21 equal to angle of incidence. [Q Ðe ¹ 0] ma 1.36 Similarly, Ðe + ÐD ¹ Ði [Q ÐA ¹ 0] 44. Incident ray 60º When a ray of light is travelling through a prism and refracted ray is parallel to the base, this condition gives the minimum angle of deviation. Glass 48. The elements B, C and D were discarded for usage by the company because for making 60º Emergent jewellery, the element should be malleable, ray ductile, lustrous and should have high melting point. So, these properties were only seen in We know that, incident ray and emergent ray elements A. So, rest of others were discarded. are parallel to each other in rectangular glass slab. Therefore, 49. As acetic acid is acidic in nature, it changes blue litmus paper into red. Ði = Ðe (corresponding angles) 50. Acetic acid gives a pungent smell of vinegar. Þ Ðe = 60° 51. When acetic acid is added in sodium bicarbonate solution, sodium acetate is formed 45. Wire at point C is at centre of curvature of along with evolution of carbon dioxide gas and concave lens, so its image C¢ will be at C, i.e. water. C = C¢ CH3COOH(aq) + NaHCO3(s) ¾® Now, for point D; CH3COONa(aq) + CO2(g)­ + H2O(l) Given, u = 10 + 10 + 1 = - 21 cm, 52. On passing excess of CO2 in limewater, the f = - 10 cm milkiness disappears due to formation of By mirror formula, calcium carbonate. 1+1= 1 Ca(OH)2(aq) + CO2(g) ¾® CaCO3(s) ¯ + H2O(l) vu f Calcium Calcium Carbon Water 1 1 -1= 1 - èæç -121÷øö carbonate Þ v = f u -10 hydroxide dioxide (limewater) Þ v = -210 53. When air is blown from mouth into test tube, 11 the limewater turns milky because the air we breathe out has more CO2. Image of point D, i.e. D¢ is at - 210 from mirror. 11 54. When CO2 gas is passed through limewater, it turns milky due to the formation of calcium The length of image of side CD is C¢ D¢ or CD¢ carbonate. = - 210 -(-20) = 20 - 210 55. In test tube-1 : Limewater turns milky after a 11 11 long time because the amount of carbon dioxide present in atmospheric air is very less = 10 cm as compared to exhaled air. 11 SAMPLE PAPER 2 46. To get an erect image from a concave mirror, In test tube-2 : Limewater turns milky the object should be placed between pole and immediately as the exhaled air is rich in carbon the focus of mirror. So, among given options dioxide. only 10 cm is less than the focal length of mirror. 56. Statement (iii) and (iv) are correct. The air exhaled through mouth turns lime water milky 47. Angle of deviation depends upon angle of at very fast rate because exhaled air contains prism (ÐA), angle of incidence (Ði) and angle more CO2 as compared to atmospheric air. of emergence (Ðe) by relation

CBSE Sample Paper Science Class X (Term I) 101 57. When object is placed at the centre of 59. As the image of head is of same size, so upper curvature of concave mirror, the image formed portion of mirror is plane. is of same size as that of object, real and inverted. The middle portion image is smaller, so the middle portion of mirror is convex and the 58. A convex mirror forms a large number of image of legs is bigger than original, so the images which are very close to each other, so lower portion of mirror is concave. they can be seen on mirror and it gives a wider field of view as shown. 60. To get a large image of object, concave mirror is used. Convex mirror When object is placed between focus and pole, Larger field view it forms an enlarged virtual image of object. But convex mirror only forms diminished image. SAMPLE PAPER 2

SAMPLE PAPER 3 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. Anil took 3 mL of sodium sulphate solution in a test tube and added 3 mL of barium chloride solution. What would he observe? (a) The solution turned red (b) White precipitation was formed (c) Yellow precipitation was formed (d) The reaction mixture became hot 2. Identify the gas A in the following experiment. Gas A Boiling tube Sodium hydrogen carbonate Burner (a) H 2 (b) CO2 (c) O 2 (d) H 2 S

CBSE Sample Paper Science Class X (Term I) 103 3. Metal H2O Metal oxide Gas Which of the following two combinations are correct ? Metal Gas evolved (i) Al Yes (ii) Fe Yes (iii) Cu No (iv) Ca No (a) (i) and (ii) (b) (ii) and (iii) (c) (i), (ii) and (iii) (d) Only (iv) 4. Which of the following correctly represents a balanced chemical equation? (a) MgO (s) + HNO 3(aq) ¾® Mg(NO 3 ) (aq) + H 2 O(l) (b) MgO (s) + 2HNO 3(aq) ¾® Mg(NO 3 ) 2 (aq) + H 2 O(l) (c) 2MgO (s) + 2HNO 3(aq) ¾® 2Mg(NO 3 ) 2(aq) + H 2 O(l) (d) 2MgO (s) + 4HNO 3(aq) ¾® 2Mg(NO 3 ) 2(aq) + 3H 2 O(l) 5. The graph has shown three pH curves A, B and C. A pH value 7C B 0 Volume of solution Which letter represents the addition of acid to solution? (a) A (b) B (c) C (d) Both A and C 6. In the reaction of ammonia with oxygen, 4NH 3 + 5O 2 ¾® 4NO + 6H 2 O Which option in the given table correctly represents the substance oxidised and the oxidising agent? Substance oxidised Oxidising agent SAMPLE PAPER 3 (a) NH 3 O2 (b) O 2 NO (c) NO NO (d) H 2 O NH 3 7. The chemical reaction between copper oxide and hydrogen can be categoriesed as (a) neutralisation reaction (b) decomposition reaction (c) combination reaction (d) redox reaction

104 CBSE Sample Paper Science Class X (Term I) 8. Which of the given options correctly represents the parent acid and base of potassium nitrate? Parent acid Parent base (a) Carbonic acid Potassium hydroxide (b) Nitric acid Potassium oxide (c) Nitric acid Potassium hydroxide (d) Hydrochloric acid Potassium oxide 9. Which of the following statement is correct regarding hydrochloric acid and water? (a) Hydrochloric acid dissociates into hydrogen and hydroxyl ions in the solution (b) Hydrochloric acid does not ionises in the solution (c) Hydrochloric acid forms hydronium ions in the solution (d) Hydrochloric acid in water produces only negative ions and releases hydrogen gas 10. Why is it important to keep the food items in refrigerator? (a) To protect them from rusting (b) To protect them from rancidity (c) To avoid contact with viruses (d) To protect them form sunlight 11. Carefully study the diagram of the human heart with labels (i) to (iv). Select the option which given correct identification and main function and/or characteristic. (i) (iv) (ii) (iii) (a) (i) Superior vena cava ® brings deoxygenated blood from lower body parts (b) (ii) Inferior vena cava ® brings deoxygenated blood from upper body parts (c) (iii) Septum ® it divides the left and right side of the heart. (d) (iv) Aorta ® carry deoxygenated blood to the body parts 12. What are the functions of the xylem? Carrying sugars Carrying water Carrying mineral ions Giving support SAMPLE PAPER 3 (a) ü r r ü (b) ü r (c) r ü r (d) r ü ü r ü ü ü Key ü = a function of xylem, r = not a function of xylem.

CBSE Sample Paper Science Class X (Term I) 105 13. Herbivores have longer small intestine because (a) they need to digest cellulose (b) they digest proteins and fats (c) digestive juices in herbivores are not functional (d) None of the above 14. The figure given below shows a diagram of closed and open stomatal pore with labels (i) to (iii). Identify the correct label with it functions. (i) Nucleus (ii) (iii) (a) (i) Guard cells – Helps in exchange of water (b) (ii) Chloroplast – Site for the photosynthesis (c) (ii) Stomatal pore – Participate in gaseous exchange during photosynthesis (d) (iii) Epidermal cells – Controls opening and closing of the stomata 15. The diagram shows the ribs and some of the muscles used in breathing. Identify the phase of breathing. Sternum Vertebrae Breathing External out intercostals Diaphragm (a) During inhalation, chest cavity is compressed due to relaxation of ribs and diaphragm (b) During exhalation, the ribs muscles and diaphragm relaxes (c) During exhalation, the chest cavity becomes larger due to relaxation of ribs and diaphragm (d) During inhalation, the diaphragm contracts and ribs muscles relaxes simultaneously 16. Observe the diagram of hemodialysis, (A ) (C ) Dialysing SAMPLE PAPER 3 (B ) solution Fresh dialysing (D) solution

106 CBSE Sample Paper Science Class X (Term I) Match the labelling referred in Column I and correlate it with Column II. Column I Column II (A) 1. It is made up of selectively permeable membrane through which patient’s blood passes. (B) 2. It is the line from artery to the pump. (C) 3. It contains solution with excess salts and urea. (D) 4. It is the line from the apparatus to vein. Codes AB C D A B CD (b) 2 3 41 (a) 4 2 1 3 (d) 2 4 13 (c) 4 2 3 1 17. The part of a lens through which a ray of light passes without suffering any deviation is called (a) centre of curvature (b) pole (c) focus (d) optical centre 18. In an experiment to trace the path of a ray of light passing through a glass prism for different value of angle of incidence, it is observed that the emergent ray Prism (a) is parallel to the incident ray (b) is parallel to refracted ray (c) is perpendicular to the incident ray (d) bends at angle to the direction of incident ray 19. Which of the following lenses would you prefer to use while reading small letters found in dictionary? (a) A convex lens of focal length 50 cm (b) A concave lens of focal length 30 cm (c) A convex lens of focal length 5 cm (d) A concave lens of focal length 5 cm SAMPLE PAPER 3 20. Consider a light ray travels from medium I to medium II to medium III of refractive indices 1, 1.23 and 2.12, respectively. Arrange the speed of light through them in decreasing order. (a) Speed of light in medium I > Speed of light in medium II > Speed of light in medium III (b) Speed of light in medium III > Speed of light in medium II > Speed of light in medium I (c) Speed of light in medium I > Speed of light in medium III > Speed of light in medium II (d) Speed of light in medium III > Speed of light in medium I > Speed of light in medium II 21. An object is placed at some distance u from a convex lens of focal length f . If image obtained is virtual, erect and magnified, then choose the correct relation of image distance v with u and f (in magnitude). (a) v < f < u (b) f < u < v (c) u < v < f (d) u < f < v

CBSE Sample Paper Science Class X (Term I) 107 22. A student used a device (X) to obtain/focus the image of a well illuminated distant building on a screen (S) as shown in the figure. Name the device used and its focal length. X S . 8 cm (a) Concave lens of focal length - 8 cm (b) Concave mirror of focal length -8 cm (c) Convex lens of focal length 8 cm (d) Convex mirror of focal length 8 cm 23. 35º Incident ray Plane mirror The total angle between the incident ray and reflected ray will be (a) 35° (b) 70° (c) 110° (d) 55° 24. Study the following diagrams in which the path of a ray of light passing through a glass prism as traced by four students P, Q, R and S as shown PQ R S Which student traced the path correctly? (c) Student R (d) Student S (a) Student P (b) Student Q 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. Potassium chlorate ¾® KCl + X Identify the correct option from the given table which represents the type of reaction SAMPLE PAPER 3 and gas evolved in reaction. Exothermic Gas evolved (a) ü r (b) r (c) ü ü ü (d) r r

108 CBSE Sample Paper Science Class X (Term I) 26. In which year, the maximum acidity of rain was recorded? pH value Rain pH value 2002 2006 2010 2014 2018 (a) 2002 (b) 2010 (c) 2018 (d) 2014 27. Zinc pieces were placed in each of the four test tubes containing different salt solutions as shown below Aluminium Zinc sulphate sulphate solution solution Zinc pieces Zinc pieces I II Iron Copper sulphate sulphate solution solution Zinc pieces Zinc pieces III IV In III and IV solutions, the change in colour is observed but not in others. What is the reason for this observation ? (a) Zinc is more reactive than iron and copper (b) Zinc is less reactive than iron and copper (c) Aluminium is less reactive than zinc, iron and copper (d) Zinc is more reactive than aluminium 28. The table shown below gives information about four substances A, B, C and D. Substances Melting point (K) Electrical conductivity in aqueous medium A 298 Poor B 1120 Good C 1850 Good D 935 Poor SAMPLE PAPER 3 Identify the substances which are ionic in nature? (a) A and B (b) B and C (c) C and D (d) A and C 29. A boy was stung by a bee. He started crying because of stung. Then her mother washed the affected area with soap and he got some relief. Which of the following statements are correct regarding this incident? I. Soap is acidic in nature. II. Soap is basic in nature. III. Acid is present in bee sting. IV. Base is present in bee sting. (a) I and III (b) I and IV (c) II and III (d) II and IV

CBSE Sample Paper Science Class X (Term I) 109 30. Which of the following setups is/are most appropriate for the evolution of hydrogen gas and its identification? (a) I and III (b) II and IV (c) I, II and II (d) Only II 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 Antacids are used to neutralise the effect of extra acid produced in the stomach during indigestion. Reason Antacids are basic in nature. 32. Assertion Sodium chloride is used for the manufacturing of many chemicals like bleaching powder, sodium hydroxide, etc. Reason The main source of common salt is sea water. 33. Assertion Amylase is the first enzyme to mix with food in digestive tract. Reason It helps in digestion of starch. 34. Assertion A rainbow is always formed in the sky after a rain shower and in the same direction as that of sun. Reason Water droplets of rain act like tiny prism. 35. The table given below shows different types of indicators. Indicators Natural Synthetic SAMPLE PAPER 3 (i) Phenolphthalein P O (ii) Methyl orange O P (iii) Vanilla essence P O (iv) Turmeric P O Which of the following gives correct information regarding the types of indicators? (a) (i) and (ii) (b) (iii) and (iv) (c) (ii) and (iv) (d) (i), (ii) and (iv) 36. Among the following choose the correct option which included the organisms that have a holozoic mode of nutrition. (a) Plasmodium and Amoeba (b) Amoeba and Paramecium (c) Parasite and Paramecium (d) Plasmodium and Paramecium

110 CBSE Sample Paper Science Class X (Term I) 37. Choose the correct statement that describes arteries. (a) They have thick elastic walls, blood flows under high pressure; collect blood from different organs and bring it back to the heart (b) They have thin walls with valves inside, blood flows under low pressure and carry blood away from the heart to various organs of the body (c) They have thick elastic walls, blood flows under low pressure carry blood from the heart to various organs of the body (d) They have thick elastic walls without valves inside, blood flows under high pressure and carry blood away from the heart to different parts of the body. 38. Which of the following statements accurately describe what happens in the mouth? (a) Amylase breaks down large proteins molecules into smaller maltose molecules (b) Chewing increases the surface area of food for digestion (c) Saliva emulsifies fats into smaller droplets (d) Teeth absorbs large insoluble molecules 39. The magnification produced by a plane mirror is +1. What does it mean? (a) Image is of same size as that of object and real (b) Image is inverted and real (c) Size of image is same as that of object but it is virtual and inverted. (d) Image is erect and virtual and of same size as that of object. 40. An object at a distance of 25 cm is slowly moved towards the pole of convex mirror. The image will become (a) shortened and real (b) diminished and virtual (c) enlarged and virtual (d) enlarged and real 41. Which of the following parts of the heart contains oxygenated blood? (a) Pulmonary veins, left atrium and aorta (b) Pulmonary artery, right ventricle and vena cava (c) Pulmonary artery, left atrium and aorta (d) Right atrium, right ventricle and aorta 42. Which of the following is not a purpose of transpiration ? (a) Supplies water for photosynthesis (b) Helps in translocation of sugar in plants (c) Cools leaf surface (d) Transport minerals from the soil to all the parts of the plant 43. A person of height 180 cm is standing in front of a plane mirror. His eyes are at a height of 172 cm from the floor. To see his full image for minimum length of mirror, the lower end of the mirror should be placed at height of SAMPLE PAPER 3 (a) 90 cm from the floor (b) 94 cm from the floor (c) 8 cm from the floor (d) 86 cm from the floor 44. White Red light Violet Prism

CBSE Sample Paper Science Class X (Term I) 111 A student observes the above phenomenon in the lab when a white light passes through a prism. His observations are I. white light splits into many colours II. angle of deviation of red is greater than violet colour III. violet light deviates most. IV. speed of red light is greater than violet light. V. wavelength of violet colour is more than red. Which one of the combination of the above statements given below is correct ? (a) (I), (II) and (III) are correct (b) (III) and (V) are correct (c) (I), (III) and (IV) are correct (d) (I), (IV) and (V) are correct 45. Plane mirror Man In the above figure, a man of height 5.8 ft is standing in front of a plane mirror. The minimum size of plane mirror to see his full image is (a) 2.9 ft (b) 4 ft (c) 5.8 ft (d) 11.6 ft 46. The refractive index of diamond is 2.42 and that of glass is 1.52. How much faster does light travel in glass than in diamond? (a) 2.42 times faster (b) 1.59 times faster (c) 1.52 times faster (d) 1.63 times faster 47. A circle of radius 10 cm is placed in front of a convex mirror of focal length 10 cm as shown below 10 cm O P If the image is half the size of object, find the radius of image of circle. (a) 10 cm (b) 1 cm (c) 5 cm (d) 2.5 cm 48. A utensil manufacturing unit tested few elements on the basis of their physical properties. Properties AB C D Malleable Yes No No Yes SAMPLE PAPER 3 Ductile Yes No No Yes Heat conductivity Yes Yes Yes No Melting point High Low Low High Which of the above elements were not approved for usage by the company? (a) A, B and D (b) A, B and C (c) B, C and D (d) A, B and D

112 CBSE Sample Paper Science Class X (Term I) 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. 2 mL of ethanoic acid was taken in test tube I and test tube II. A red litmus paper was introduced in test tube I and a pH paper was introduced in test tube II. The experiment was performed by four students A, B, C and D; and they reported their observation as given in the table. Students Action on red litmus paper Action on pH paper A Turned blue Turned pink B Remains unchanged Turned green C Turned blue Turned blue D Remains unchanged Turned pink 49. Which set of observation is correct? (a) A (b) B (c) C (d) D (d) 0 50. What is the approximate pH of ethanoic acid? (d) Colourless (d) mild acidic (a) 4 (b) 2 (c) 6 51. What will be the effect on phenolphthalein in ethanoic acid? (a) Pink (b) Red (c) Yellow 52. The dark blue colour on pH paper indicates that the sample is (a) highly basic (b) highly acidic (c) mild basic Case II. The figure shown below represents the flow of blood in the human heart. The blood passes through the heart two times to supply once to the whole body. So, it is called double circulation of blood. 53. In humans, right auricle receives deoxygenated blood from (a) aorta (b) vena cava SAMPLE PAPER 3 (c) pulmonary vein (d) pulmonary artery 54. The pulmonary arteries arises from the (a) right auricle (b) left ventricle (c) right ventricle (d) left auricle 55. What is the correct route for blood flow in human? (a) Left atrium ® Left ventricle ® Lungs ® Right ventricle ® Right atrium (b) Left atrium ® Left ventricle ® Right ventricle ® Right atrium ® Lungs (c) Right atrium ® Right ventricle ® Left ventricle ® Left atrium ® Lungs (d) Right atrium ® Right ventricle ® Lungs ® Left atrium ® Left ventricle

CBSE Sample Paper Science Class X (Term I) 113 56. In mammals, veins differ from arteries in having 1. Low pressure 2. Thicker walls 3. Internal valves 4. High pressure (a) 1 and 3 (b) 1 and 2 (c) 3 and 4 (d) 2 and 3 Case III. An Overhead Projector (OHP), like a film or slide projector, uses light to project an enlarged image on a screen. In an OHP, the source of the image is a page-sized sheet of transparent plastic film (also known as foils) with the image to be projected either printed or hand-written/drawn. These are placed on the glass surface of the projector, which has a light source below it and a projecting mirror and lens assembly above it as shown below. They are widely used in education and business. It works on the same principle as a slide projector, in which a focussing lens projects light from an illuminated slide onto a projector screen, where a real image is formed. Plane Screen mirror Image Focal lens Object Concave mirror 57. What kind of lens is used to make the overhead projector? (a) Convex lens (b) Concave lens (c) Bifocal lens (d) Flat lens 58. How the image obtained will be real and erect? (a) When it passes through the lens and directly obtained on the screen. (b) When it passes through the lens and gets reflected on the mirror to be obtained on the screen. (c) The screen used, automatically makes the image erect and real. (d) Both (b) and (c) 59. A concave mirror is used here in place of convex mirror. Why? SAMPLE PAPER 3 (a) Concave mirror gives real image (b) Convex mirror gives real image (c) Concave mirror gives virtual image (d) Convex mirror gives virtual image 60. The power of convex lens is ............. and that of concave lens is ....... . (a) positive, negative (b) negative, positive (c) negative, negative (d) positive, positive

OMR SHEET SP 3 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) 115 Answers 1. (b) 2. (b) 3. (c) 4. (b) 5. (b) 6. (a) 7. (d) 8. (c) 9. (c) 10. (b) 11. (c) 12. (d) 13. (a) 14. (c) 15. (b) 16. (d) 17. (d) 18. (d) 19. (c) 20. (a) 21. (d) 22. (c) 23. (c) 24. (b) 25. (b) 26. (d) 27. (a) 28. (b) 29. (c) 30. (d) 31. (a) 32. (b) 33. (b) 34. (d) 35. (c) 36. (b) 37. (d) 38. (b) 39. (d) 40. (b) 41. (a) 42. (b) 43. (d) 44. (c) 45. (a) 46. (b) 47. (c) 48. (c) 49. (d) 50. (a) 51. (d) 52. (a) 53. (b) 54. (c) 55. (d) 56. (a) 57. (a) 58. (b) 59. (a) 60. (a) EXPLANATIONS 1. The reaction between sodium sulphate 6. In a given reaction, NH3 is oxidised to NO by solution and barium chloride solution addition of oxygen or removal of hydrogen produces white coloured precipitate of barium sulphate along with sodium chloride solution. and O2 itself gets reduced, hence, it is an oxidising agent. So, option (a) is correct. Na2SO4 (aq) + BaCl2(aq) ¾® 2NaCl(aq) 7. The reaction between copper oxide and Sodium sulphate Barium Sodium chloride hydrogen is given below : chloride CuO (s) + H2(g) ¾® H2O (l) + Cu (s) + BaSO4 ¯ Copper Hydrogen Water Copper Barium sulphate oxide (white ppt.) It is a redox reaction because CuO is reduced 2. When sodium hydrogen carbonate is heated in to Cu and H2 is oxidised to H2O in this a test tube then carbon dioxide is evolved. The reaction. Both oxidation and reduction occurs other products are sodium carbonate and water. in this reaction. So, it is a redox reaction. 2NaHCO3 ¾D® Na2CO3 + H2O + CO2 ­ 8. Potassium nitrate (KNO3) salt is formed by reaction between potassium hydroxide (parent Sodium hydrogen Sodium Water Carbon base) and nitric acid (parent acid). carbonate carbonate dioxide (A) HNO3(aq) + KOH(aq) ¾® KNO3(aq) + H2O(l) Hence, gas A is carbon dioxide (CO2). Nitric Potassium Potassium water acid hydroxide nitrate 3. Aluminium, iron and calcium react with water 9. When hydrochloric acid is treated with water, to produce hydrogen gas while copper does not react with water. then ionisation takes place and hydronium (i) 2Al (s) + 3H2O (l) ¾® Al2O3(s) + 3H2(g) ions and chloride ions are formed. (ii) 3Fe (s) + 4H2O (l) ¾® Fe3O4(s) + 4H2(g) HCl(aq) + H2O(l ) ¾® H3O+(aq) + Cl-(aq) (iii) Cu (s) + H2O (l) ¾® No reaction (iv) Ca (s) + 2H2O (l) ¾® Ca(OH)2(aq) + H2(g) Hydrochloric Water Hydronium Chloride So, from these four reactions, only (iv) combination is incorrect. acid ion ion Hence, option (c) is correct. 10. The food items which contains fats and oils get oxidised which results in change of small and 4. The chemical reaction in option (b) is balanced taste in them. This process of slow oxidation of SAMPLE PAPER 3 oil and fat is known as rancidity to prevent MgO (s) + 2HNO3(aq) ¾® Mg(NO3)2(aq) food spoilage and rancidity. That’s why they + H 2 O(l) are kept in refrigerator to slow down the rate of oxidation and hence, they can be fresh for The total number of atoms of each element are longer time period. equal on both sides of the equation. 11. The septum is the dividing wall between the 5. According to the graph, there are three curves, right and left side of the heart. Interauricular which are A, B and C, which represent base, septum seprates right and left atrium and acid and neutral solution respectively interventricular septum seprates right and left according to their pH value. As base (A) has ventricle. pH > 7, acid (B) has pH < 7 and neutral (C) has pH = 7. Hence, option (b) is correct. 12. Xylem is a conducting tissue in plants. It helps in the transportation of water and minerals from roots to all parts of the plant.

116 CBSE Sample Paper Science Class X (Term I) Apart of conducting water and minerals, it also 20. Refractive index of medium I, m I = 1 acts as supportive tissue. Refractive index of medium II, m II = 1.23 Refractive index of medium III, m III = 2.12 13. Herbivores consume plant and grass based Speed of light in medium food which contain cellulose. Digestion of µ1 cellulose takes a longer time. Hence, they need Refractive index of medium a longer small intestine to allow complete digestion of cellulose. \\ vI > vII > vIII 14. (ii) Stomatal pores participate in gaseous 21. Convex lens forms a virtual, erect and exchange during photosynthesis and also magnified image only when the object is responsible for large amount of water loss. placed between lens and focus as shown. Incorrect options can be corrected as A' (i) Guard cell-helps in exchange of gases. A (iii) Chloroplast-site for photosynthesis. B' F B F 15. When we breathe out, the muscles between the ribs relax causing the ribcage to move u downward and inward and the diaphragm f relaxes and moves upward. As chest cavity v becomes smaller, air is pushed out from the lungs. \\ u < f < v (in magnitude) 16. The correct labelling is 22. Device X is a convex lens of focal length 8 cm. As the rays coming from a distant building (A) Line from artery to pump through a convex lens converge at its focus. (B) It is line from apparatus to vein. 23. The situation is shown below (C) It is tube made up of a selectively N permeable membrane. The patient’s blood is passed through these tubes. 55° 55° (D) It is used dialysing solution which contains 35° 35° M¢ urea and excess salts. M 17. When a ray of light passes through optical O centre of the lens (both concave and convex), it will emerge out undeviated (as shown in figure) From figure, Ði = Ðr = 55° \\ Ði + Ðr = 55° + 55° = 110° F1 O F2 F1 O F2 24. Student Q has traced the path correctly. When a ray of light travels from a rarer (air) to Convex lens Concave lens a denser medium of prism, it bends towards the normal to the first surface and when a 18. The light ray while passing through a glass ray of light travels from a denser medium of prism suffers refraction at the two faces of prism to rarer medium (air), it bends away prism. So, the emergent ray will bend at an from the normal to the second surface. angle to the direction of incident ray. SAMPLE PAPER 3 25. When potassium chlorate is heated, it decomposes to give potassium chloride and oxygen. 19. Convex lens is used as magnifying glass. 2KClO3(s) ¾D® 2KCl(s) + 3O2(g) As, focal length, f=1 Potassium Potassium Oxygen P chlorate chloride Convex lens of focal length 50 cm has power So, potassium chlorate is heated to form 2 D, whereas convex lens of focal length 5 cm potassium chloride which is an endothermic has power 20 D. Hence, for better performance, reaction and oxygen gas is evolved. Hence, option (b) is correct. its focal length should be small.

CBSE Sample Paper Science Class X (Term I) 117 26. Lower the pH value, higher the acidity of 33. Both A and R are true, but R is not the correct SAMPLE PAPER 3 solution. So, in 2014, the pH value was the explanation for A. lowest, hence, the maximum acidity of rain was recorded in 2014. Food digestion process begins in the mouth. Mouth contains salivary glands that secrete 27. In III and IV solutions, the change in colour is saliva which contain salivary amylase enzyme. observed due to displacement reaction because This enzyme breaks down the starch into Zn is more reactive than iron and copper simple sugars. according to reactivity series. 34. A is false and R is true. So, Zn displaces iron and copper from their A rainbow is always formed in the opposite respective salt solutions and form zinc direction of the sun. The water droplets act like sulphate solutions. small prism. Due to the dispersion of light and internal reflection, different colours reach the i.e. Zn(s) + FeSO4(aq) ¾® ZnSO4(aq)+ Fe(s) observer’s eye. Zn(s) + CuSO4(aq) ¾® ZnSO4(aq)+ Cu(s) 35. Phenolphthalein, methyl orange and vanilla On the other hand, aluminium is more reactive essence are made in laboratories. Therefore, than zinc, hence, it is not displaced by zinc and they are known as synthetic indicators. But therefore, no change in solution is observed in turmeric is present in nature, hence, it is natural solution I. indicator. Zinc does not react with its own sulphate Therefore, option (c) shows correct information. solution so, no colour change is observed in solution II. 36. Amoeba and Paramecium are unicellular organism with holozoic mode of nutrition. In 28. Ionic compounds are crystalline solids and Amoeba food is engulfed with the help of hard in nature. Hence, they have high melting pseudopodia while in paramecium food is point and they can conduct electricity in engulfed with the help of hair-like cilia. aqueous medium. Therefore , substances B and C are ionic in nature. 37. Arteries are the vessels which carry blood away from the heart to various organs of the 29. Both II and III statements are correct. When body. Since, the blood emerges from the heart bee stings, it injects formic acid into the skin under high pressure, the arteries have thick, that causes pain and irritation. When soap elastic walls. Veins collect the blood from solution is used on the affected area, it gives different organs and bring it back to the heart. relief because soap solution is basic in nature. They do not need thick walls because the blood is no longer under pressure, instead they Acid + Base ® Salt + Water have valves that ensures that the blood flows in only one direction. This process is known as neutralisation reaction. So, the formic acid which cause pain and 38. Chewing increases the surface area of food. irritation gets neutralised by base present in Large food particles are broken down into soap solution. Hence, gives relief. small particles by chewing with the help of teeth. Salivary amylase breaks down large 30. Set up II is the most appropiate for evolution starch molecules into smaller maltose of hydrogen gas and its identification. molecules. Bile emulsifies fats into smaller Zn (s) + 2NaOH(aq) ¾® Na2ZnO2(aq) + H2­(g) droplets. To test the evolution of hydrogen gas properly, delivery tube should not dip in the solution. 39. If magnification is +1, then it means 31. Both A and R are true and R is the correct m = hi = 1 explanation of A. ho Antacids are basic in nature, therefore they are Þ hi = ho used to neutralise the acidity produced in The image size is same as that of object size, stomach due to indigestion. since the magnification is positive, the image is erect and virtual. 32. Both A and R are true but R is not the correct explanation of A. 40. A convex mirror always forms a diminished and virtual image of object placed at any Sodium chloride is used in the preparation of position on principal axis. many chemicals because its processing method is cheap and can be produced in large quantity.

118 CBSE Sample Paper Science Class X (Term I) 41. Pulmonary veins carry oxygenated blood from 49. Only D student observed the correct lungs to the heart. Left atrium and left information because red litmus paper remains ventricle contain oxygenated blood. unchanged in ethanoic acid, while pH paper turns pink in acidic solution. Aorta carries oxygenated blood from heart to different body organs/parts. 50. The approximate pH of ethanoic acid is 4 as the pH paper shows pink colour on its addition. 42. Absorption of water and minerals by plants directly depends on the transpiration pull 51. Phenolphthalein becomes colourless in generated by loss of water through stomata, ethanoic acid because it turns colourless in but translocation of sugar is a physiological acidic medium and gives pink colour in process and is not related to transpiration loss alkaline medium. of water. 52. pH paper gives dark shades of blue in alkaline 43. The minimum length of mirror for full image, or basic medium. Hence, if any sample shows dark blue colour on pH paper, it means it is l = 180 = 90 cm highly basic in nature. 2 53. In human, right auricle receives deoxygenated \\The lower end of the mirror should be at blood from vena cava. The superior vena cava - 172 and inferior vena cava carries deoxygenated x = 180 - éêë90 + (180 2 )ù blood from different body parts to the heart. ûú 54. The pulmonary arteries arises from the right = 180 -(90 + 4) ventricle and carry deoxygenated blood to the = 86 cm from the floor lungs for oxygenation. 44. Splitting of white light into different colours is 55. The deoxygenated blood enters the right called dispersion. The colour violet has a atrium through the vena cava. This blood smaller wavelength, so it deviates most while passes to the right ventricle and through the red colour deviates least due to its longer pulmonary artery this deoxygenated blood is wavelength. As, the angle of deviation of red is pumped into lungs for oxygenation. Then, the least, so the speed of red colour is most. oxygenated blood is transported to left atrium through the pulmonary veins and then moves 45. To see the full image of man, the size of mirror to the left ventricle from where it is pumped required is half the height of man, i.e. into the whole body through aorta. \\ l = H = 5.8 = 2.9 ft 56. Veins are the blood vessels present throughout 22 the body. They carry deoxygenated blood from the heart to the body. The blood pressure in 46. Given, m g = 1.52, m d = 2.42 arteries in much greater than that in the veins. The valves are present in veins to prevent As, vg = md æçèQ m µ 1 ö÷ø back flow of blood. vd m g v 57. Convex lens is used here to focus the beam of \\ vg = 2.42 = 1.59 light. vd 1.52 58. The image when passed through the lens is 47. Given, m= 1, ho = 2r = 20 cm inverted and then it gets reflected by the plane 2 mirror. So, the erect and real image is obtained on screen. \\ Magnification, m = hi Þ 1 = hi ho 2 20 59. Concave mirror is used here because it can give real image, while convex mirror gives SAMPLE PAPER 3 or hi = 10 cm virtual image. \\ Radius of image = hi = 10 = 5 cm 60. The focal length of convex lens is positive, so 22 its power is positive. Similarly, focal length of concave lens is negative and its power is also 48. The elements B, C and D were not approved by negative. company for usage because for utensil manufacturing because for usage of an element, it should be malleable, ductile, good conductor of heat and have high melting point. A has all these properties. Hence, A was approved and rest were disapproved.

P SAMPLE PAPER 4 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. Aman took an iron nail and immersed it in copper sulphate solution, for few minutes. What would he observe? (a) The surface of iron nails acquire black coating (b) The colour of solution changes to green (c) The colour of solution fades away (d) No reaction takes place 2. Identify the gas evolved in the following experiment. Stand Burning matchstick Capillary tube Cork Clamp HCl (dil.) Solid particles of Zn Burner (a) H 2 (b) CO 2 (c) O 2 (d) Cl 2

120 CBSE Sample Paper Science Class X (Term I) 3. Metal carbonate Dil. HCl Metal salt Gas Which of the following two combinations are correct? Metal carbonate Gas evolved (i) Copper Yes (ii) Silver No (iii) Zinc Yes (iv) Sodium No (a) (i) and (ii) (b) (ii) and (iii) (c) (iii) and (iv) (d) (i) and (iii) 4. Which of the following correctly represents a balanced chemical equation? (a) Cu(s) + HNO 3(aq) ¾® Cu(NO 3) 2(aq) + NO 2(g) + H 2O(l) (b) Cu(s) + 4HNO 3(aq) ¾® Cu(NO 3) 2(aq) + 4NO 2(g) + 2H 2O(l) (c) Cu(s) + 4HNO 3(aq) ¾® Cu(NO 3) 2(aq) + 2 NO 2(g) + 2H 2O(l) (d) Cu(s) + 3HNO 3(aq) ¾® Cu(NO 3) 2(aq) + NO 2(g) + 2H 2O(l) 5. The graph given below have 3 curves which are A, B and C. Which letter represents the relationship between pH and the concentration of solution? B SAMPLE PAPER 4 C pH value A Conc. of H+ (a) A (b) B (c) C (d) Both A and C 6. In the reaction of hydrogen sulphide with chlorine, H 2S + Cl 2 ¾® S + 2HCl Which option in the given table correctly represents the substance oxidised and the reducing agent? Substance oxidised Reducing agent (a) H 2S H 2S (b) HCl S (c) Cl 2 HCl (d) S H 2S 7. The reaction between copper sulphate and hydrogen sulphide can be classified as (a) displacement reaction (b) double displacement reaction (c) combination reaction (d) decomposition reaction

CBSE Sample Paper Science Class X (Term I) 121 8. Which of the given option correctly represents the parent acid and base of sodium acetate ? Parent acid Parent base (a) HCl NaOH (b) CH 3COOH Na 2O (c) CH 3COOH NaOH (d) Na 2CO 3 HCl 9. While diluting a concentrated acid, how can one protects himself from the heat generation? (a) Add acid to water with constant stirring (b) Add water to acid with constant stirring (c) Add water to acid followed by base (d) Add base to acid with constant stirring 10. Why there is an importance of chemical equation in chemical reactions? (a) A chemical equation tells us about the substances involved in a reaction. (b) A chemical equation tells us about the atoms or molecules of the reactants and products involved in a reaction. (c) A chemical equation gives information about the symbols and formulae of the substances involved in a reaction. (d) All of the above 11. Carefully study the diagram of human digestive system with labels (i), (ii), (iii) and (iv) and choose the incorrect pair. (ii) Oesophagus (food pipe) Salivary glands Stomach Tongue (iii) (iv) Liver Diaphragm Gall bladder (stores bile) Bile duct Rectum Appendix SAMPLE PAPER 4 (i) Anus Human digestive system (a) (i) Small intestine – Fat digestion (b) (ii) Buccal cavity – Starch digestion (c) (iii) Pancreas – Release pancreatic juice for protein digestion (d) (iv) Large intestine – Carbohydrate digestion

122 CBSE Sample Paper Science Class X (Term I) 12. The diagram given below shows the human excretory system. Kidneys Ureters X Identify the function of part labelled as X. (a) To excrete urea (b) To produce urea (c) To produce urine (d) To store urine 13. Peristaltic movements refers to (a) contraction and expansion of lungs (b) contraction and relaxation of heart (c) contraction and expansion of walls of food pipe (d) movement of blood throughout the body 14. The figure given below shows a human circulatory system with labels (i) and (iv). Identify the correct labels with its functions and/or characteristics (iv) (ii) (i) (iii) SAMPLE PAPER 4 (a) (i) Pulmonary vein ® has low oxygen concentration and high pressure (b) (ii) pulmonary artery ® has high oxygen concentration and low pressure (c) (iii) Vena cava ® has high oxygen concentration and high pressure (d) (iv) Aorta ® has high oxygen concentration and high pressure 15. In the figure given below, the structures associated with human kidneys are marked (X, Y and Z). X Y Aorta Z Vena cava The relative concentration of urea in (a) X is sometimes higher than Y (b) Y is always higher than Z (c) Y is always lower than Z (d) Z is sometimes lower than X

CBSE Sample Paper Science Class X (Term I) 123 16. Observe the diagram of human respiratory system. A B C D Match the labelling referred in Column I and correlate with characteristics/functions in Column II. Column I Column II A 1. Air passages inside lungs that branch like tree limbs B 2. Its walls comprises of C-shaped cartilaginous rings C 3. It forms the base of chest cavity D 4. It is the common pathway for air and the food Codes AB C D A B CD (b) 2 4 1 3 (a) 1 2 3 4 (d) 4 2 1 3 (c) 4 2 3 1 17. In an experiment, the image of distant object formed by a concave mirror is obtained on a screen. The focal length of the mirror is the distance between (a) mirror and the object (b) mirror and the screen (c) object and the screen (d) half the distance between mirror and screen 18. Which of the following ray diagrams is correct for the ray of light incident on a lens shown in figure? F OF F OF SAMPLE PAPER 4 (B) (A) OF O F FF (D) (C) (a) A (c) C (d) D (b) B

124 CBSE Sample Paper Science Class X (Term I) 19. Which of the following is not an example of refraction of light? (a) A lemon kept in water in glass tumbler appears to be bigger than its actual size. (b) The letters appear to be lower when viewed through glass slab placed over the document. (c) A pencil partially immersed in water appears to be bent. (d) The coin at bottom of water tank appears to be raised when viewed from top. 20. A ray of light passes through 3 media A, B and C. Wavelength of light in medium A, medium B and medium C is 2000 Å, 3000 Å, 4000 Å, respectively. Based on this data arrange the frequencies of light in correct order. (a) Frequency in medium A < frequency in medium B < Frequency in medium C. (b) Frequency in medium C < Frequency in medium B < Frequency in medium A. (c) Frequency in medium C = 2 ´ Frequency of medium A (d) Frequency in medium A = Frequency in medium B = Frequency in medium C. 21. Jay have two thin lenses, convex and concave of focal length 25 cm, then which of the following is correct about their focal length? (a) fconcave = fconvex (b) fconcave > fconvex (c) fconcave < fconvex (d) fconcave = 1 fconvex 22. Ram while performing an experiment on tracing the path of a light ray passing through a rectangular glass slab, measured three angles marked as q 1, q 2 and q 3 in the figure. q1 q2 q3 Which one of the following is correct? (a) angle q 1 is less than angle q 2 but equal to angle q 3 (b) angle q 2 is equal to angle q 3 (c) Sum of angle q 1 and angle q 2 is equal to angle q 3 (d) angle q 3 is greater than angle q 2 23. A ray of light incident on a prism is refracted as shown. The correct path of light corresponds to SAMPLE PAPER 4 (i) (ii) (a) (ii) (iii) (iv) (d) (iii) (b) (i) (c) (iv)

CBSE Sample Paper Science Class X (Term I) 125 24. Earth Increasing altitude The Earth’s atmosphere consists of layers of varying densities. The air layer of atmosphere whose temperature is less than the other layer behaves as (a) optically rarer medium (b) optically denser medium (c) optically inactive medium (d) neither denser nor rarer 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. Zn + H 2 O ¾® A + B (Steam) Identify the correct option from the given table which represents the type of reaction and gas evolved. Displacement reaction Gas evolved (a) ü û (b) û ü ü (c) ü û (d) û 26. The graph given below depicted a record of the pH value of rain in different years. In which year, the concentration of hydrogen ion is minimum? 6.00 2000 2002 2004 2008 2010 2014 2018 5.00 Rain pH value 4.00 pH 3.00 value2.00 1.00 0 (a) 2000 (b) 2004 (c) 2008 (d) 2014 27. Four students were asked by their teacher to arrange the set ups I-IV as given below SAMPLE PAPER 4 Dilute HCl Dilute NaOH Dilute HCl Dilute NaOH Na2CO3 Zinc Zinc Na2CO3 (I) (II) (III) (IV) Among the four setups, only IV does not evolve gas.

126 CBSE Sample Paper Science Class X (Term I) What is the reason for different behaviour in test tube IV? (a) Neutralisation takes place (b) Precipitation reaction occurs. (c) Na 2CO 3does not react with dil. NaOH (d) Na 2CO 3 reacts with dil.NaOH and form carbonic acid and water. 28. The table shown below gives information about four elements A, B, C and D. Elements Electronic configuration A 2, 8, 2 B 2, 8, 7 C 2, 8, 6 D 2, 8, 3 Identify the elements which can make ionic compound. (a) A and B (b) B and C (c) C and D (d) A and C 29. Sunita observed that the yellow stain of curry on a white shirt remains unchanged when it is dipped with vinegar but it turns reddish brown when it washed with soap. What might be the reason for her observation? I. Soap is basic in nature. II. Soap is acidic in nature. III. Turmeric is a natural indicator which changes its colour to red in bases. IV. Turmeric is a natural indicator which changes its colour to red in acids. (a) I and II (b) I and III (c) II and IV (d) II and III 30. Four students I, II, III and IV were asked to examine the changes for blue and red litmus paper strips with dil. HCl (solution A) and dil. NaOH (solution B). The following observation were reported by the four students. The sign (-) indicating no colour changes. I. Litmus A B Blue – Red Red – Blue SAMPLE PAPER 4 II. Litmus AB Blue Red Red – Blue III. Litmus A B Blue Red Red Red Blue Blue

CBSE Sample Paper Science Class X (Term I) 127 IV Litmus A B Blue Blue Blue Red Red Red Which of the above observation(s) is/are correct? (a) I and II (b) III and IV (c) II and IV (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 The following chemical equation, 2C6H6 + 7 O 2 ¾® 4 CO2 + 3H2O 2 is a balanced chemical equation. Reason In a balanced chemical equation, the total number of atoms of each element is equal on both sides of the equation. 32. Assertion Acetic acid (CH 3 COOH) is a weak acid. Reason Acetic acid produces very little OH - ions on dissociation in water. 33. Assertion Exchange of oxygen and carbon dioxide occurs between trachea and the blood vessels. Reason Oxygen diffuses into the blood vessels and carbon dioxide diffuses out from the blood vessels. 34. Assertion Newton showed that the seven coloured lights of the spectrum can be recombined to give back white light. Reason When a beam of white light is passed through a glass prism, a band of seven colours is formed on a white screen. 35. Which one of the following set of observation will be correct (ü mark shows reaction takes place, (û shows reaction does not take place)? Metal added Solution taken I. Zn ZnSO 4 FeSO 4 CuSO 4 Al2 (SO4 )3 II. Fe III. Cu û ü û û IV. Al û ü ûü û û û üû SAMPLE PAPER 4 ü üü (a) I (b) II (c) III (d) IV 36. The correct sequence of anaerobic reaction in yeast is (a) Glucose ¾Cyt¾opl¾asm® Pyruvate ¾Mi¾toc¾hon¾dri®a Ethanol + Carbon dioxide (b) Glucose ¾Cyt¾opl¾asm® Pyruvate ¾Cyt¾opl¾asm® Lactic acid (c) Glucose ¾Cyt¾opl¾asm® Pyruvate ¾Mi¾toc¾hon¾dri®a Lactic acid (d) Glucose ¾Cyt¾opl¾asm® Pyruvate ¾Cyt¾opl¾asm® Ethanol + Carbon dioxide

128 CBSE Sample Paper Science Class X (Term I) 37. The following changes take place in an athlete’s body during 100 m race. Which change occurs first? (a) Increased availability of oxygen to muscles (b) Increased breathing rate (c) Increased carbon dioxide concentration in the blood (d) Increased production of carbon dioxide by muscles 38. Which one of the following statement is incorrect about the human circulatory system? (a) Valves ensure that the blood does not flow backwards (b) Arteries are thin walled to maintain blood pressure in them (c) The normal systolic pressure is about 120 mm of Hg and diastolic pressure is about 80 mm of Hg. (d) Pulmonary vein carry oxygenated blood from lungs 39. The power of a concave lens of focal length 1 mm is (a) 0.01 D (b) 100 D (c) 0.001 D (d) 1000 D 40. When a plane mirror is rotated through a certain angle (q), the reflected ray turns through a twice or much and the size of image (a) becomes twice the size of object (b) becomes half the size of object (c) becomes negligibly small (d) remains same as that of object 41. What is the nature of the food in the stomach and what is done for the pancreatic enzymes to act? (a) Acidic, made more acidic (b) Acidic, made alkaline (c) Alkaline, made acidic (d) Alkaline, made more alkaline 42. During anaerobic alcoholic fermentation by yeast, alcohol is formed (a) in the yeast cell’s vacuole (b) in the yeast cell’s mitochondrion (c) outside the yeast cell (d) within the yeast cell 43. Refractive index of ethanol is 1.36 and it is known that benzene is optically denser than ethanol. The refractive index of benzene could be (a) 1.35 (b) 1.28 (c) 1.34 (d) 1.50 44. A SAMPLE PAPER 4 B B' F P A' The above mirror has a focal length of 10 cm. The object is placed at a distance of 30 cm from the pole. Find the magnification of object. (b) 1 (a) - 1 2 2 (d) - 1 (c) 1 4 4

CBSE Sample Paper Science Class X (Term I) 129 45. Principal F1 F2 axis f (A) O F2 f (B) While studying the given above diagrams, Radha concluded the following (i) The image of the object will be inverted (ii) The point of convergence of parallel beam by convex lens is focal point. (iii) The image in case (B) is virtual one (iv) The beam of light, incident on the convex lens (B) is not parallel to principal axis. Which of the above statements are correct? (a) (i) and (ii) (b) (iii) and (iv) (c) (i), (ii) and (iv) (d) (i), (ii), (iii) and (iv) 46. A ray of light undergoes refraction from medium I to medium II as shown in figure. If speed of light in medium I is v, then its value in medium II is, N X 60º I 30º II Y (a) 3v (b) v N' (d) v 3 2 (c) 2v 47. A mark on the bottom of the liquid appears to rise by 0.1 m. The depth of the liquid is 1 m. Find the refractive index of the liquid. (a) 0.9 (b) 1.1 (c) 1.33 (d) 1.5 48. A metallic interior designing company tested few elements on the basis of their SAMPLE PAPER 4 physical properties. Properties AB CD Malleable Yes No No Yes Ductile Yes No No Yes Melting point High Low Low High Lustre No Yes No Yes

130 CBSE Sample Paper Science Class X (Term I) Which of the above elements were disapproved for usage by the company? (a) A, B, C (b) B, C, D (c) A, B, D (d) A, C, 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 The sample pieces of five metals M, N, O, P and Q are added to the tabulated salt solutions separately. The results observed are shown in the table given below. Metal Salt solutions FeSO 4 CuSO 4 ZnSO 4 AgNO 3 M No change No change No change A coating on metal N Grey deposit Brown coating No change A coating on metal O No change No change No change No change P No change – No change A coating on metal Q Brownish-red deposit Brown coating Grey coating New coating Read the observations carefully and give the answer of the following questions 49. Which is the most reactive metal? (a) N (b) O (c) P (d) Q 50. Which is the least reactive metal? (a) M (b) O (c) Q (d) N 51. What will happen when these metal reacts with acid? (a) Salt is formed along with H 2 gas (b) Salt is formed along with CO 2 gas (c) Metal oxide is formed along with water (d) Metal oxide is formed along with hydrogen gas. SAMPLE PAPER 4 52. Which type of reaction is observed in the given data? (a) Decomposition reaction (b) Displacement reaction (c) Neutralisation reaction (d) Precipitation reaction

CBSE Sample Paper Science Class X (Term I) 131 Case II. Digestion is a catabolic process where complex and large components of food are broken down into simpler forms with the help of hydrolytic enzymes which are absorbed by different parts of the body. Answer the questions on the basis of your understanding of the following table and related concepts. Parts of the human Main functions Main type of Sources of Substances Products of digestive system enzymes the enzymes on which digestion acting enzymes act Mouth, teeth, tongue Food broken Amylase X Starch Complex and salivary glands down into smaller sugars pieces, some digestion of starch Oesophagus Transports food to — ——— stomach Stomach Digestion of Protein protein fragments Protease Y Proteins and some amino acids Small intestine Final digestion Amylase, Simple followed by lipase and Complex absorption of protease nutrients sugars, fatty sugars, fats Z acids, and protein glycerol and fragments amino acids Salts, vitamins and water absorbed Large intestine from wastes, — ——— undigested wastes collected Anus Elimination of — ——— wastes 53. Based on the information in the table, which substance breaks down starch. (a) Lipase (b) Amylase (c) Trypsin (d) Protease 54. What is the composition of gastric juice? (b) HCl, Lipase, Amylase (d) Mucus, Pepsin, Bile (a) HCl, Pepsin, Lipase (c) Pepsin, HCl, Mucus 55. Identify the correct source of enzymes in mouth, stomach and small intestine labelled SAMPLE PAPER 4 as X, Y and Z. (a) X-Salivary glands, Y-Gastric glands, Z-Pancreas and small intestine (b) X-Salivary glands, Y-Gastric glands, Z-stomach (c) X-Saliva, Y-HCl, Z-Liver (d) X-Parotid glands, Y-Mucous, Z-Pancreas 56. Name the parts of the human digestive system where digestion of food does not take place. (i) Oesophagus (ii) Mouth (iii) Large intestine (iv) Anus

132 CBSE Sample Paper Science Class X (Term I) Choose the correct option. (b) (i), (iii) and (iv) (a) (i) and (iv) (d) (i), (ii), (iii) and (iv) (c) (iii) and (iv) Case III. Uma needs a telescope to see the stars in the night sky. She knows that telescopes are used to observe objects which are very far from us. So, she decided to make a simple telescope. She used two lenses L1 and L2 as objective lens and eyepiece, respectively. A parallel beam of light is focused by the objective lenses L1which is bigger in size and then light passes through an eyepiece L2 (smaller lens) forming a magnified image. Eye L1 L2 (objective lens) (eye piece) So, to see far away, she needed a big powerful lens. Unfortunately, she realised that big lenses are very heavy in holding a telescope at right position. 57. Based on the diagram of telescope, which lens is used by Uma? (a) Plano-convex lens (b) Double convex lens (c) Bi-focal lens (d) Concave lens 58. If the power of L1and L2 are in the ratio of 16 : 9, what would be the ratio of the focal length of L2 and L1? (a) 3 : 4 (b) 16 : 9 (c) 9 : 16 (d) 4 : 3 59. While doing this demonstration, her friend noted some observations as follows (i) The power of the objective lens of a telescope kept as small as possible. (ii) The aperture of objective lens or mirror of a telescope takes as large. (iii) The objective of the telescope have large focal length. (iv) The power of eyepiece and objective is same. Which one combination of the above statements is correct? (a) (i), (ii) and (iii) are correct (b) (ii) and (iv) are correct (c) (iii) and (iv) are correct (d) (i), (iii), (iv) are correct 60. Convex lens is not used in which one of the following? (a) Telescope (b) Microscope (c) Flashlight (d) Magnifying glass SAMPLE PAPER 4

OMR SHEET SP 4 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)

134 CBSE Sample Paper Science Class X (Term I) Answers 1. (b) 2. (a) 3. (d) 4. (c) 5. (a) 6. (a) 7. (b) 8. (c) 9. (a) 10. (d) 11. (d) 12. (d) 13. (c) 14. (d) 15. (c) 16. (b) 17. (b) 18. (a) 19. (b) 20. (d) 21. (c) 22. (a) 23. (c) 24. (b) 25. (c) 26. (d) 27. (c) 28. (d) 29. (b) 30. (d) 31. (d) 32. (c) 33. (d) 34. (b) 35. (d) 36. (d) 37. (d) 38. (b) 39. (d) 40. (d) 41. (b) 42. (d) 43. (d) 44. (a) 45. (c) 46. (a) 47. (b) 48. (a) 49. (d) 50. (b) 51. (a) 52. (b) 53. (b) 54. (c) 55. (a) 56. (b) 57. (b) 58. (b) 59. (a) 60. (c) EXPLANATIONS 1. The reaction involved 9. While diluting a concentrated acid, one should add acid to water with constant stirring to Fe + CuSO4 ¾® FeSO4 + Cu avoid any mishappening related to heat (Blue) (Green) generation throughout the process as dilution of conc. acid is an exothermic reaction. Due to the displacement reaction, the formation 10. All the given statements are correct about the of FeSO4 (green in colour) takes place. importance of chemical equation in a chemical reaction. 2. When metal reacts with dil. HCl, it produces 11. Option (d) is incorrect pair. In large intestine salt and hydrogen gas. So, according to the absorption of water and salt from undigested food material occurs. The rest of the material is experiment, removed from the body via anus. Zn + 2HCl ¾® ZnCl2 + H2 12. The part labelled as X is urinary bladder. The urinary bladder is a muscular sac in the (diluted) pelvis, just above and behind the pubic bone. The function of urinary bladder is to store 3. When metal carbonate reacts with dil. HCl, it urine. produces salt, carbon dioxide and water. 13. The lining of alimentary canal has muscles that contract rhythmically in order to push the food Metal carbonate+ dil. HCl ¾®Salt + CO2 + H2O forward in the food pipe. These peristaltic So, (i) and (iii) are correct combination among movements occur all along the gut. others. 14. In aorta, blood has high oxygen concentration 4. Chemical equation (c) is balanced one as total as it has entered from lungs and is transported number of atoms of each element are equal on to the different parts of the body under high both sides of the equation. pressure. Cu(s) + 4HNO3(aq) ¾® Cu(NO3 )2(aq) + 2 NO2(g) + 2 H2O(l) 15. The structures are labelled as X—Renal vein Y—Renal artery 5. As pH value is indirectly proportional to Z—Ureter concentration of H+ ions, thus, ‘A’ curve is correct. The renal artery (Y) carries oxygenated blood to the kidneys from the heart. This blood 6. H2S + Cl2 ¾® S + 2 HCl contains negligible amount of urea. On the other hand, the ureters (Z) transport urine In this reaction, H2S is oxidised to S by from the kidneys to the urinary bladder. removing hydrogen atoms. Hence, H2S acts as reducing agent as well because the substance The urine contains comparatively high amount of urea to be excreted out. Thus, the relative that oxidised is called reducing agent. concentration of urea in Y is always lower than that in Z. SAMPLE PAPER 4 7. The chemical reaction between copper sulphate and hydrogen sulphide involves: CuSO4 + H2S ¾® CuS + H2SO4 It is a double displacement reaction because both ions, Cu2 + and H+ exchange their positions and form two new compounds, CuS and H2SO4. 8. Sodium acetate (CH3COONa) is formed by reaction between CH3COOH (parent acid) and NaOH (parent base). CH3COOH + NaOH ® CH3COONa + H2O

CBSE Sample Paper Science Class X (Term I) 135 16. The structures are labelled as 23. The correct path of light which is incident on a prism is A - Trachea B - Pharynx 24. Densities of different layers of earth depend C - Bronchioles D - Diaphragm upon the presence of molecules in it. The layer which is at cold place has closely spaced Trachea is also called windpipe, is a tube that molecules rather than layer at hot place where serves as a passage for air. The walls of trachea molecules are apart. comprises C-shaped cartilaginous rings which prevents trachea from collapsing. So, the layer whose temperature is less than other layer behaves as optically denser Pharynx is a common pathway for the air and medium. the food. The flap-like structure called 25. Zn + H2O ¾® ZnO + H2­ epiglottis is present that prevents food particles from going into the food pipe. (Steam) Bronchi are subdivided into smaller tubes In this reaction zinc oxide is formed with called bronchioles. Bronchioles deliver air to evolution of hydrogen gas and this reaction is diffuse network of alveoli. a type of displacement reaction because oxygen is displaced from hydrogen to zinc. Diaphragm forms the base of chest cavity. 26. In the graph, the pH value touched the higher 17. The image of distant object is formed at focus. in year 2014. Hence, where pH value is So, the focal length of the mirror is the distance highest, the concentration of H+ is lowest between the mirror and the screen. because pH is inversely proportional to concentration of H+ ions. 18. A ray of light passing through the principal focus of a convex lens after refraction from a convex 27. In IV setup, Na2CO3 does not react with dil. lens, will emerge parallel to the principal axis or NaOH, hence there is a no evolution of gas. vice-versa. If a ray of light passing through the optical centre of the lens, emerges without any 28. A : 2, 8, 2 and C : 2, 8, 6 deviation after refraction and if light moves ‘A’ can lose 2 electrons and ‘C’ can gain 2 along principal axis, the same rule applies. electrons to fulfill their stable electronic configuration. ‘A’ easily transfer its 2 electrons 19. Due to refraction of light at the surface of to C and make ionic bond. water, a lemon inside water appears to be bigger than actual, a pencil partially immersed 29. In acidic medium, turmeric does not change its in water appears to be bent, a coin at bottom of yellow colour while in basic medium, it water tank appears to be raised and the letter changes its colour to red. Therefore, on when viewed from glass slab appears to raised scrubbed with soap, it turns reddish-brown over the document. which means soap is basic in nature. 20. As the ray of light passes through different 30. Only observation II is correct among others. media, its frequency does not change with the Because on addition of acid, blue litmus turns value of refractive index. red and on addition of base, red litmus turns blue. However, acid does not change colour of So, frequency in medium A, medium B and red litmus and base does not change the colour medium C is equal. of blue litmus. 21. Focal length of concave lens, fconcave = - 25 cm 31. A is false but R is true. In a balanced chemical equation, the total Focal length of convex lens, fconvex = 25 cm number of atoms of each element are equal on Þ fconcave < fconvex both sides of the equation moreover, the correct balanced chemical equation is 22. Since, in glass slab experiment, 2 C2H6 + 7 O2 ¾® 4 CO2 + 6 H2O i SAMPLE PAPER 4 q1 q2 r e q3 Ði > Ðr but Ðe = Ði Þ q 1 < q 2 but q 1 = q 3

136 CBSE Sample Paper Science Class X (Term I) 32. A is true, but R is false. acidic food from the stomach is made alkaline by the action of bile. Acetic acid is a weak acid because it does not dissociates completely into ions (H+ and 42. During anaerobic alcoholic fermentation by CH3COO-) in water. yeast, alcohol is formed within the yeast cell. It is a incomplete breakdown of pyruvate into 33. A is false, but R is true. ethanol and carbon dioxide to release energy. Exchange of gases like oxygen and carbon dioxide occurs between the alveoli and the The reaction of anaerobic alcoholic blood vessels. Oxygen diffuses from alveoli fermentation can Be Summarised as : into the blood vessels and carbon dioxide diffuses from the blood vessels to the alveoli. Glucose ¾In¾cyt¾opl¾asm® Pyruvate + Energy (6 molecules ) (2 molecules ) 34. Both A and R are true, but R is not correct explanation of A. ¾Ab¾sen¾ce¾of ¾oxy¾ge®n Ethanol + CO2 + 2 ATP in years Newton showed that the reverse of dispersion ( 2 molecules ) (2 molecules ) (Energy) of light is possible. The light gets dispersed when passes through the first prism. The 43. As benzene is denser than ethanol. So, its second prism receives all the seven coloured refractive index must be greater than ethanol. rays from first prism and recombines them into i.e. mbenzene = 1.50 original white light. 44. Given, u = - 30 cm, f = - 10 cm 35. Al being most reactive element, reacts with all By mirror formula, the solutions taken. 1+1= 1 vu f Al + ZnSO4 ¾® Al2(SO4)3 + Zn Al + FeSO4 ¾® Al2(SO4 )3 + Fe 1+ 1 = 1 Al + CuSO4 ¾® Al2(SO4 )3 + Cu v - 30 - 10 36. Glucose is converted into pyruvate (glycolysis) Þ 1= 1 - 1 =- 1 in the cytoplasm of the cell. It is the first stage v 30 10 15 of respiration. After glycolysis, pyruvate gets converted into ethanol and carbon dioxide or v = - 15 cm - (- 15) during anaerobic respiration in cytoplasm of - 30 yeast. Magnification, m= - v = Þm= - 1 u 2 37. The first change that occurs in athelete’s body 45. The image formed by convex lens (when object is at infinity) is at focus, real and inverted. In is decrease in oxygen availability in muscle case (A), the beam of light is coming parallel to principal axis while in case (B) the beam of cells and cells start anaerobic respiration. In light incident on lens is not parallel to principal axis but the converging point is focus of the order to provide energy for 100 m race, lens. respiration increases in athelete’s muscles and CO2 is produced. 46. Given, i = 90° - 60° = 30° 6 CO2 + C6H12O6 ¾® 6 H2O + 6CO2 + Energy 38. Arteries are thick walled due to high pressure r = 90° - 30° = 60° of oxygenated blood in them. Veins have thin Using Snell’s law, m = sin i = v sin r v¢ walls because the deoxygenated blood is no longer under high pressure. Þ v¢ = sin r ´ v = sin 60° ´ v sin i sin 30° 39. Given, focal length = 1 mm = 10- 3 m SAMPLE PAPER 4 \\ P= 1 = 3 ´ 2 ´ v = 3v f(in m ) 2 P = 1 3 47. Given, real depth = 1 m 10- Apparent depth = 1 - 0.1 = 0.9 m Þ P = 1000 D Refractive index of the liquid = Real depth 40. Rotation of plane mirror, through any angle Apparent depth doesn’t affect the size of image. =1 41. The pancreatic enzymes are optimally active in 0.9 alkaline pH in the small intestine. Thus, the Þ m = 1.1

CBSE Sample Paper Science Class X (Term I) 137 48. For metallic interior designing, the element Z—Pancreas and small intestine, which should have lustre, ductility, malleability and secretes enzymes in the small intestine. high melting point and D have all these properties. So, except D, all the other elements 56. In the human alimentary canal, the parts were disapproved. where digestion of food does not takes place is the oesophagus, the large intestine and the 49. Q is the most reactive metal because it reacts anus. with all salt solutions. 57. As shown in the given diagram, Uma would 50. O is the least reactive metal because it shows need double convex lens in order to make least reactivity with salt solutions and it does telescope. not react with any solution. 58. Given, P1 = 16 51. Acid + Metal ¾® Salt + H2 ­ P2 9 When an acid reacts with metal, there is As, P µ 1 formation of salt with evolution of hydrogen gas. f 52. The reactions between metal and salt solution Þ P1 = f2 = 16 involve displacement reaction depends on the P2 f1 9 reactivity of metal. 59. The objective lens of small power has a large 53. Amylase is a carbohydrate digestive enzyme, focal length which gives a high magnifying which is responsible for the breakdown of power of the telescope. starch into smaller molecules. If the aperture of objective lens is large, it 54. The gastric juice secreted by the gastric glands gathers more light rays, so that brighter image of the stomach includes HCl, pepsin and is formed. mucus. The power of eyepiece is larger than objective 55. The labelled source of enzymes are due to its small focal length. X—Salivary glands, which secretes amylase in 60. Convex lens is used in telescopes, the mouth. microscopes, magnifying glass, etc. Concave lens is used in flashlights to get a parallel Y—Gastric glands, which secretes gastric juices beam of light. in the stomach. SAMPLE PAPER 4

SAMPLE PAPER 5 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. 10 mL of HCl and 10 mL of NaOH solutions are taken in two separate beakers labelled I and II, respectively. On adding zinc granules to both beakers, it is observed that at room temperature. (a) Gas is evolved vigorously in both the beakers (b) Gas is evolved vigorously in beaker I and not in the beaker II (c) Gas is evolved vigorously in beaker II but not in the beaker I (d) No gas is evolved in either of the two beakers 2. What type of reaction is observed in this beaker ? Iron H2O container CaO (a) Endothermic (c) Displacement (b) Exothermic (d) Precipitation

CBSE Sample Paper Science Class X (Term I) 139 3. Metal oxide Dil.HCl Salt ? Which of the following two combinations are correct ? Metal Gas evolved 1. Cu No 2. Fe No 3. Mg Yes 4. Zn Yes (a) 1 and 2 (b) 2 and 3 (c) 3 and 4 (d) 1 and 4 4. Which of the following reaction involves the formation of yellow coloured product ? (a) 2 KClO3 ¾H¾e¾at® 2 KCl + 3O2 (b) NH3 + HCl ¾® NH4Cl (c) CuSO4 + H2S ¾® CuS + H2SO4 (d) 2Pb 3O4 ¾¾D ® 6PbO + O2 5. The graph given below depicts the neutralisation reaction in which NaOH is added to HCl. 14 C pH 7 B value A O Volume of NaOH added (mL) Which letter denotes the highly basic area? (a) A (b) B (c) C (d) Both B and C 6. In the following reaction, 3Fe + 4H 2O ¾® Fe 3O 4 + 4H 2 Identify the correctly representation of the substance reduced and the oxidising agent. Substance reduced Oxidising agent (a) Fe Fe (b) H2O H2O SAMPLE PAPER 5 (c) Fe3O4 H2 (d) 4H2 Fe 3 O4 7. When zinc reacts with dilute hydrochloric acid, then (a) the surface of zinc becomes brighter (b) the surface of zinc becomes black and dull (c) the metal turns into powder (d) the reaction mixture turns green

140 CBSE Sample Paper Science Class X (Term I) 8. Which of the given options correctly represents the parent acid and base of ammonium sulphate? Parent acid Parent base (a) HCl NH3 NH4 OH (b) H2 SO4 NaOH (c) NH3 (d) H2 SO4 NH3 9. The products formed by chlor-alkali process are (a) H2, Cl 2 and NaOH (b) Cl 2, Na 2CO3 and H2O (c) NaOH , Cl2 and NaCl (d) NaCl, Cl 2 and H2 10. How can you specify the chemical reaction between calcium oxide and water ? (a) Change in colour of product (b) Change in temperature of mixture (c) Change in the state of mixture (d) Evolution of hydrogen gas 11. The diagram shows part of the human gas exchange system. W X Y Z Select the option which gives correct identification and main function and/or characteristics of the shown labels. (a) X–Trachea : It serves as a passage for food. (b) Y– Bronchiole : It deliver air to the capillaries. (c) W - Larynx : It serves as chamber for both respiratory and digestive functions. (d) Z - Bronchus : It act as passage way that leads from the trachea to lungs. 12. The diagram shows the human gut. Which numbered structures secrete digestive enzymes? 6 Oesophagus 5 (food pipe) SAMPLE PAPER 5 1 2 4 3 (a) 1-Stomach, 2-Pancreas, 3-Small intestine, 4-Large intestine (b) 1-Stomach, 2-Pancreas, 3-Small intestine, 6-Mouth (c) 2-Pancreas, 3-Small intestine, 4-Large intestine, 5-Liver (d) -2-Pancreas, 3-Small intestine, 5-Liver, 6-Mouth

CBSE Sample Paper Science Class X (Term I) 141 13. Which of the following structures is involved in gaseous exchange in woody stem of a plant? (a) Stomata (b) Lenticel (c) Guard cell (d) Epidermis 14. When a person eats some egg white, proteins and water enter the stomach. Which substances are found leaving the stomach and leaving the small intestine? Leaving the stomach Leaving the small intestine (a) Amino acids and water Amino acids and water (b) Fatty acids, glycerol and water Fatty acids, glycerol and water (c) Protein and water Fatty acids and glycerol (d) Protein, amino acids and water Water 15. Identify the correct phase of nutrition in Amoeba represented in the diagram given below. Nucleus (a) Food particle (b) (c) Food particle (d) (a) Amoeba ingests the food particle with the help of cilia present all over the body (b) The finger-like extension fuses over the food particle to form food vacuole (c) The undigested food comes out of the body with the help of pseudopodia (d) Inside the Amoeba the simpler substances diffused into the nucleus 16. Observe the diagram of human circulatory system. Vena cava receiving Aorta blood from upper body Pulmonary arteries B Pulmonary SAMPLE PAPER 5 veins Vena cava receiving C blood from lower body Valves A D Interventricular septum(dividing wall)

142 CBSE Sample Paper Science Class X (Term I) Match the labelling referred in Column I and correlate it with Column II. Column I Column II A 1. Oxygenated blood from lungs transported to it. B 2. Oxygenated blood from it transported to body part. C 3. Deoxygenated blood from it goes to lungs. D 4. Deoxygenated blood from body flows to it. Codes ABCD ABCD (b) 3 4 2 1 (d) 4 1 3 2 (a) 4 3 2 1 (c) 3 4 1 2 17. A person travelling at day time in foggy weather is not able to see things clearly on road because of (a) refractive index of the fog is very high (b) light suffers internal refraction by droplets (c) fog absorbs light rays (d) light is scattered by the tiny water droplets 18. Choose the correct depiction for dispersion of white light on passing through a prism. White light A Red White light A Green (i) Violet (ii) Red White light A White light A Violet Blue Yellow Green (iii) (iv) (a) (i) (b) (ii) (c) (iii) (d) (iv) 19. Linear magnification of an image formed by a mirror is 3. The mirror is 2 (a) a plane mirror (b) a concave mirror (c) a convex mirror (d) Both concave mirror and convex mirror 20. A convex lens made up of glass is immersed in a liquid of refractive index greater than that of glass as shown in the figure SAMPLE PAPER 5 Choose the correct statement of the following. (a) Convex lens will act as diverging lens. (b) Convex lens will disappear in liquid. (c) Convex lens will form magnified image in liquid. (d) Convex lens remains converging lens.

CBSE Sample Paper Science Class X (Term I) 143 21. Three students A, B and C measured the focal length of a convex lens and labelled the distance as f1, f2 and f3 , respectively. Student A saw sharp image, student B saw slightly larger blurred image and student C saw a slightly smaller blurred image on the screen. The relation between the three measurements would most likely be (a) f1 = f2 = f3 (b) f1 < f2 and f3 (c) f3 < f1 < f2 (d) f1 < f2 and f1 = f3 22. Which of the following is the correct diagram of a ray light after reflection at the mirror? P FC P FC (a) (b) P FC PF (c) (d) 23. To form an erect image twice the size of an object by using a convex lens of focal length 20 cm, the object should be placed at a distance d from the optical centre of lens. Here, d is (a) d = 40 cm (b) d = 20 cm (c) d > 20 cm (d) d < 20 cm 24. If a light ray IM is incident on the surface AB as shown, identify the correct emergent ray. I M B A D N O C (b) Ray NQ RS PQ (a) Ray NP (c) Ray NR (d) Ray OS 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. Lead tetraoxide ¾¾D ® PbO + X SAMPLE PAPER 5 Identify the correct option from the given table which represents the type of reaction and gas evolved (X). Endothermic Gas evolved (a) P O (b) O P (c) P P (d) O O