Science - 10 Sample Paper 1

SAMPLE Paper 1 [Easy Concept] Time Allowed : 3 hrs. Maximum Marks : 80 General Instructions: (i) The question paper comprises four sections A, B, C and D. There are 36 questions in the question paper. All questions are compulsory. (ii) Section–A - question no. 1 to 20 - all questions and parts thereof are of one mark each. These questions contain multiple choice questions (MCQs), very short answer questions and assertion - reason type questions. Answers to these should be given in one word or one sentence. (iii) Section–B - question no. 21 to 26 are short answer type questions, carrying 2 marks each. Answers to these questions should in the range of 30 to 50 words. (iv) Section–C - question no. 27 to 33 are short answer type questions, carrying 3 marks each. Answers to these questions should in the range of 50 to 80 words. (v) Section–D – question no. - 34 to 36 are long answer type questions carrying 5 marks each. Answer to these questions should be in the range of 80 to 120 words. (vi) There is no overall choice. However, internal choices have been provided in some questions. A student has to attempt only one of the alternatives in such questions. (vii) Wherever necessary, neat and properly labeled diagrams should be drawn. SECTION – A 1. Name a device that helps to maintain a potential difference across a conductor. Or Why is the series arrangement not used for domestic circuits? 2. What is the magnification of the images formed by plane mirrors and why? 3. Which one of the following will undergo fastest bio-degradation? (a) Mango seed (b) Wood (c) Mango peel (d) Mango pulp 4. Out of Li and K, which have stronger metallic character and why? 5. Write suitable conditions necessary for seed germination. 6. What is emulsification? Or Which pancreatic enzyme is effective in digesting proteins? 7. Which enzyme present in saliva breaks down starch? 8. Write two characteristics associated with rancid food. 9. Urine is yellow in colour. Why? Or Why does bread taste sweet on mastication? 10. What type of lens is an air bubble inside water? 11. What is the role of decomposers in the environment? Or Why is it necessary to conserve our environment? 12. In which part of alimentary canal digestion does not occur? Or What is alimentary canal? 13. Name the part of our eyes that helps us to focus near and distant objects simultaneously. Sample Papers 53

For question numbers 14, 15 and 16, two statements are given- one labeled Assertion (A) and the other labeled 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 correct explanation of the assertion. (b) Both A and R are true, but R is not the correct explanation of the assertion. (c) A is true, but R is false. (d) A is false, but R is true. 14. Assertion: Iron displaces copper from copper sulphate solution. Reason: Iron is more reactive than copper. 15. Assertion: Blind spot is a small area of the retina which is insensitive to light where the optic nerve leaves the eye. Reason: There are no rods or cones present at the junction of optic nerve and retina in the eye. 16. Assertion: The maleness of a child is determined by the ‘Y’ chromosome in zygote. Reason: Human offspring’s sex is determined through father’s sex chromosomes. Or Assertion: Human, frog and bird have a common ancestor. Reason: Limbs of human, bird and frog are homologous. Answer Q. No 17 - 20 contain five sub-parts each. You are expected to answer any four sub-parts in these questions. 17. Read the following and answer any four questions from 17 (i) to 17 (v). Mendel’s experiments on inheritance of traits. Mendel used a number of visible contrasting characters of garden pea like round/wrinkled RR yy rr YY seeds, tall/short plants, white/violet flowers, etc. (round, green) (wrinkled, yellow He made crosses between pea plants with different Ry rY characters; there were no halfway or intermediate characters. Only one of the parental traits appeared F1 in the F1 generation. When the F1 plants were Rr Yy self-pollinated, the F2 progeny consists of plants (round, yellow) with both the traits. When a cross is made between a tall plant with Rr Yy Rr Yy F1 F1 round seeds, with a short plant with wrinkled seeds, RY Ry rY ry the F1 progeny plants were all tall with round F2 plants. When the F1 plants are self-pollinated, the RY 315 round, yellow 9 F2 progeny consisted of some tall plants with round RRYY RRYy RrYY RrYy 3 seeds and some short plants with wrinkled seeds; 3 these two are the parental types of combinations Ry 1 RRYy RRyy RrYy Rryy 16 of traits. rY 108 round, green RrYY RrYy rrYY rrYy 101 wrinkled, yellow There were also some new combinations like tall 32 wrinkled, green plants with wrinkled seeds and short plants with ry RrYy Rryy rrYy rryy 556 seeds round seeds. Independent inheritance of two separate traits, shape and colour of seeds 54 Together with®  EAD Science—10

(i) Which of the following type of trait appeared in F1 generation? (a) Dominant (b) Recessive (c) Both (a) and (b) (d) None of these (ii) Which of the following type of trait remained hidden in F1 generation? (a) Dominant (b) Recessive (c) Both (a) and (b) (d) None of these (iii) Which of the following trait you observed in F2 progeny, when F1 plants were self pollinated? (a) Dominant (b) Recessive (c) Both (a) and (b) (d) None of these (iv) Which of the following ratio of both traits obtained in F1 progeny? (a) 9 : 3 : 3 : 1 (b) 3 : 1 (c) 2 : 2 (d) None of these (v) Which of the following genetic material is responsible for the inheritance of traits? (a) Gene (b) DNA (c) RNA (d) None of these 18. Read the following and answer any four questions from 18 (i) to 18 (v). Study the table related to the values of electrical resistivities of some substances, in ohm-metre, at 20 °C are given as follows: Silver Copper Tungsten Mercury Iron Nichrome 1.60×10–8 1.62×10–8 5.2×10–8 94×10–8 10×10–8 10×10–6 (i) Which of the following substance is preferred to be used for electrical transmission lines? (a) Silver (b) Copper (c) Tungsten (d) Iron (ii) Which of the following represent correct relationship between electrical resistivity (r), resistance (R), area of cross-section (A) and length (l)? (a) r = RA (b) r = l l RA ρR (c) r = 1 (d) A = l lRA (iii) Electrical resistivity of a given metallic wire depends upon (a) its length (b) its thickness (c) its shape (d) nature of the material (iv) Nichrome is the material that you would advice to use in the heater element of electric heating device because (a) It is an alloy of metals (b) Its resistivity is higher than that of its constituent metals (c) It neither gets oxidised nor burn easily at high temperature (d) All of these. (v) Out of Cu, Fe, W and Hg which one of the following will you prefer to use in electrical wire for domestic use? (a) Cu (b) Fe (c) W (d) Hg Sample Papers 55

19. Read the following and answer any four questions from 19 (i) to 19 (v). Shyam participated in a group discussion in his interschool competition on the practical application of light and was very happy to won the award for his school. On that very evening, his father celebrated the day with a family dinner. At a particular moment, Shyam observed in a curve plate, the image of a person’s mobile sitting on his back side. Person’s mobile was fell off which the person didn’t know about it. Shyam went to the person and informed about this. The person was thankful to Shyam. (i) From which one of the following side of the plate Shyam observed this incident? (a) North (b) South (c) Outward curve (d) Inward curve (ii) The part of the curve plate was acting like which of the following type of mirror? (a) Convex (b) Concave (c) Plane (d) None of these (iii) Which of the following nature and size of image formed by this mirror? (a) Virtual, erect, diminished (b) Real, erect, diminished (c) Inverted, erect, diminished (d) None of these (iv) An object is placed at a large distance in front of a convex mirror of radius of curvature 40cm. How far is the image behind the mirror? (a) 20 cm (b) 40 cm (c) 60 cm (d) 80 cm (v) An object at a distance of +15 cm is slowly moved towards the pole of a convex mirror. The image will get (a) shortened and real (b) enlarged and real (c) enlarge and virtual (d) diminished and virtual 20. Read the following and answer any four questions from 20 (i) to 20 (v). A student fixes a sheet of white paper on a drawing board. He place a bar magnet at the centre of it. He sprinkles some iron filings uniformly around the bar magnet. Then he taps the board gently and observes that the iron filings arrange themselves in a particular pattern. (i) Inside the magnet, the field lines moves (a) from north to south (b) from south to north (c) away from south pole (d) away from north pole (ii) Which of the following statement is not correct about the magnetic field? (a) Magnetic field lines form a continuous closed curve. (b) Magnetic field line do not interest each other. (c) Direction of tangent at any point on the magnetic field line curve gives the direction of magnetic field at that point. (d) Outside the magnet, magnetic field lines go from South to North pole of the magnet. (iii) A current through a horizontal power line flows from south to North direction. The direction of magnetic field line 0.5m above it is (a) North (b) South (c) West (d) East 56 Together with®  EAD Science—10

(iv) Which of the following method is applied to produce magnetic field? (a) Bar magnet (b) Straight wire carrying current (c) Circular coil carrying current (d) All of these (v) Which of the following is correct property of magnetic field lines? (a) The magnetic field lines never intersect each other (b) Magnetic field lines are closed curve (c) Magnetic field lines have both direction and magnitude (b) All of these SECTION – B 21. (a) Three acidic solutions A, B and C have pH=0, 3 and 5 respectively. (i) Which solution has the highest concentration of H+ ions? (ii) Which solution has the lowest concentration of H+ ions? (b) How can concentrated sulphuric acid be diluted? Describe the process. Or State reason for the following statements: (a) Tap water conducts electricity whereas distilled water does not. (b) Dry hydrogen chloride gas does not turn blue litmus red whereas dilute hydrochloric acid does. 22. What are stomata? What is their role in respiration? 23. A concave lens of focal length 15 cm forms an image 10 cm from the lens. How far is the object placed from the lens? Or List four specific characteristics of the images of the object formed by convex mirrors. 24. What is meant by periodicity of properties of elements ? Why are the properties of elements placed in the same group of the periodic table similar? 25. (a) Why is carbon tetravalent? (b) Which element exhibits the property of catenation to maximum extent and why? 26. (a) What is F2 generation? (b) Why traits such as intelligence and knowledge cannot be passed on to the next generation? SECTION – C 27. Draw a diagram of the front view of human heart and label any six parts including at least two, that are concerned with arterial blood supply to the heart muscles. Or Draw the structure of a nephron and label the following parts: Glomerulus, Bowman’s capsule, Renal artery. 28. (a) Give suitable reason to justify the following statement: An aqueous solution of NaCl is neutral but an aqueous solution Na metal is basic. (b) Mention the pH aqueous solution of the following salts as 7, more than 7, less than 7. KCl, Na2CO3 Sample Papers 57

29. “Energy flow in food chains is always unidirectional.” Justify this statement. Explain how the pesticides enter a food chain and subsequently get into our body. 30. (a) oWcchuerns:SO2 gas is passed through the saturated solution of hydrogen sulphide, the following reaction SO2 + 2H2S → 2H2O + 2S For this reaction, name the substance oxidised and reduced. (b) Name the oxidising agent and the reducing agent. 31. An element ‘X’ belongs to 3rd period and group 16 of the Modern Periodic Table (a) Determine the number of valence electrons and the valency of ‘X’. (b) Write the molecular formula of the compound when ‘X’ reacts with hydrogen and write its electron dot structure. (c) Name the element ‘X’ and state whether it is metallic or non-metallic. 32. Define an alloy. How are alloys prepared? How do the properties of alloys change when iron is mixed with: (a) a small quantity of carbon (b) nickel and chromium 33. (a) Describe an activity to show that the colors of white light splitted by a glass prism can be recombined to get white light by another identical glass prism. Also draw a ray diagram to show the recombination of the spectrum of white light. (b) An object is placed perpendicular to the principal axis of a convex lens of focal length 20 cm. The distance of the object from the lens is 30 cm. Find: (i) the position (ii) the magnification and (iii) the nature of the image formed. SECTION – D 34. Answer the following: (a) Name any four asexual methods of reproduction. (b) Explain the method of reproduction with diagram by which an Amoeba reproduces. (c) Give one difference between fission and fragmentation. Or (a) Name an organism that reproduces by spores. List two advantages of reproduction by sporulation. (b) G ive one function of each part of embryo: (i) plumule (ii) radicle (iii) cotyledons 35. (a) A student was given Mn, Zn, Fe and Cu metals. Identify which of them (i) will not displace H2 from dil. HCl. (ii) will react only with steam to give H2 (g). (iii) will give H2 with 5% HNO3. Write the chemical reactions involved. (b) (i) Show the formation of Na2O by the transfer of electrons between the combining atoms. (ii) Why are ionic compounds usually hard? 58 Together with®  EAD Science—10

36. (a) In the circuit diagram shown, calculate: 6W D 4W (i) current flowing through arms AB, AC and CDE CE (ii) potential difference across AB, CD and DE (iii) effective resistance of the circuit. 12 W AB 1.5 V (b) Work done in moving 5 C charge across the ends of a conductor is 100 J. If the potential at the one end of the conductor is 10V, find the potential at the other end of this conductor. Or (a) List the factors on which the resistance of a conductor in the shape of a wire depends. (b) Why are metals good conductors of electricity whereas glass is a bad conductor of electricity? Give reason. (c) Why are alloys commonly used in electrical heating devices? Give reason. Sample Papers 59

Answers 1. Cell or battery eliminator. Or (i) All appliances do not get same potential in series arrangement. (ii) All appliances cannot be individually operated. 2. The magnification of the images formed by plane mirrors is 1 as the size of the image is equal to the size of object. 3. (d) 4. K because it has larger size and more tendency to lose electron. 5. Conditions necessary for seed germination are water, temperature and oxygen. 6. Breakdown of large gloubule fats into smaller fats droplets is known as emulsification. Or Trypsin is the pancreatic enzyme which is effective in digesting proteins. 7. The saliva contains an enzyme called salivary amylase that breaks down starch. 8. Unpleasant smell and unpleasant taste. 9. It is because urine contains uric acid, urea and ammonical salts which give yellow colour. Or Salivary amylase act on starch of food and change it into a sweet sugar called maltose. 10. Air bubble acts as a concave lens in water as water is denser than air. 11. Decomposers decompose dead remains of plants and animals. They return the simple components to soil and help in maintaining the steady state of ecosystem and therefore, create a balance in the environment. Or It is necessary to conserve our environment to prevent depletion of natural resources and environmental damage, thereby sustaining life. 12. Large intestine Or It is a long tube extending from mouth to anus in which digestion and absorption of food takes place. 13. Ciliary muscle 14. (b) Both A and R are true, but R is not the correct explanation of the assertion. 15. (a) Both A and R are true, and R is correct explanation of the assertion. 16. (a) Both A and R are true, and R is correct explanation of the assertion. Or (a) Both A and R are true, and R is correct explanation of the assertion. 17. (i) (a) dominant (ii) (b) recessive ( iii) (c) Both dominant and recessive when F1 plants were self pollinated while some traits are inherited independently also. (iv) (b) 3 : 1 (v) (a) Gene 60 Together with®  EAD Science—10

18. (i) (a) Silver metal should be preferred for making the transmission line as its resistivity is lowest among the given metals. However due to its high cost, copper is preferred over silver as its resistivity is also low for electrical transmission line. (ii) (a) (iii) (d) (iv) (d) (v) (a) 19. (i) (c) Outward curve (ii) (a) Convex mirror (iii) (c) Virtual, erect and diminished (iv) (a) T he rays coming from an object placed at large distance can be considered as a parallel rays. After reflection from it, they appear to meet at its focus which is 40/2 = 20 cm. (v) (d) Convex mirror always formed virtual and diminished image. 20. (i) (a) Magnetic field inside the magnet moves from south to north pole. (ii) (d) Outside the magnet, magnetic field line emerges from North-pole and moves towards south- pole. (iii) (d) East (iv) (d) (v) (d) 21. (a) (i) Solution ‘A’ with pH = 0 has the highest concentration of H+ ions. (ii) Solution ‘C’ with pH = 5 has the lowest concentration of H+ ions. (b) Dilution of concentrated acid is an exothermic process. If water is added to a concentrated acid, the heat generated may cause the mixture to splash out and cause burns on the person. However, when the acid is added to water slowly and stirred constantly, the mixture will not splash out as the heat generated will be absorbed, by water. So, we should always add acid to water in small installments and never to add water to acid. Or (a) Tap water contains ions which conduct electricity, distilled water does not contain ions. (b) Dry HCl does not form ions but HCl gives H+ and Cl–. 22. Stomata are tiny openings found on the surface of the leaves. Stomata functions in gaseous exchange between the plant and the atmosphere The oxygen of from the air diffuses inside the leaf calls when stomata open and carbon dioxide diffuses out of the leaves through it. 23. For concave lens, f = –15 cm, v = –10 cm [  f = focal length, v = image distance, u = object distance] We know, 1 = 1 – 1   ⇒  1 = 1 – 1 = 1 – 1 = – 1 f v u u v f –10 –15 30 Therefore, u = –30 cm The negative value of u indicates that the object should be placed at 30 cm in front of the concave lens. Or Properties of image formed by a convex mirror: (i) It always formed behind the mirror, between the pole and its focus (ii) The image is always virtual and erect. (iii) The size of image is always smaller than the object. (iv) Magnification is always positive. Sample Papers 61

24. The repetition of similar properties of elements after a regular interval is called periodicity of properties of elements. The properties of elements placed in same group are similar due to same number of valence electrons. 25. (a) It is because carbon can share form electrons to complete its octet. (b) Carbon shows catenation to maximum extent because it forms strong covalent bonds. 26. (a) The generation produced by the offspring to F1 generation, i.e. first generation as parent is called F2 generation. (b) Trait such as intelligence and knowledge are acquired traits which do not bring any change in the DNA of the germ cell and therefore, cannot passed to next generation. 27. External Structure of Human Heart Or Structure of a Nephron 28. (a) NaCl is a salt of NaOH (strong base) and HCl (strong acid). 2Na + 2H2O → 2NaOH + H2 Sodium reacts with water of form NaOH which is strong base, therefore solution is basic. (b) (i) KCl pH = 7 (ii) Na2CO3 pH > 7 29. The energy flow through different steps in the food chain is unidirectional. The energy captured by autotrophs does not revert back to the solar input and it passes to the herbivores, i.e. it moves progressively through various trophic levels. Thus energy flow from sun through producers to omnivores is in single direction only. 62 Together with®  EAD Science—10

Pesticides are sprayed to kill pests on food plants. The food plants are eaten by herbivores and alongwith the food, pesticides are also eaten by the herbivores. Herbivores are eaten by carnivores and alongwith the herbivore animal, pesticide also enters the body of the carnivore. Man eat both plants and animals and pesticide alongwith food enters the body of human. Concentration of pesticides increases as we move upward in the food chain and the process is called bio-magnification. 30. (a) SO2 + 2H2S → 2H2O + 3S Sulphur Hydrogen dioxide sulphide (b) H2S is oxidised to sulphur and is a reducing agent whereas SO2 is reduced to sulphur and is an oxidising agent. 31. (a) Electronic configuration of X – 2, 8, 6; valence electrons-6; Valency = 8 – 6 = 2 HXH (b) Formula with hydrogen- H2X or H2S Valency of sulphur = 2 Electron dot structure of H2X (c) The element is Sulphur and it is non-metal. 32. Alloy is a homogeneous mixture of two or more metals or a metal and a non-metal. It is prepared by first melting the primary metal and then dissolving the other elements in it in a definite proportion. It is then cooled to the room temperature. (a) An alloy called steel is formed when iron is mixed with carbon. It becomes hard and strong. (b) On mixing iron with Ni and Cr, it becomes very hard, does not rust and is called stainless steel. 33. (a) Description of activity: When a glass prism is used to obtain a Second spectrum of sunlight, a second identical prism in an inverted position with respect to the first A B′ Prism C′ light White spot position will allow all the colours of spectrum B RecombinationWhite to recombine. Thus, a beam of white light will White light emerge from the other side of the second prism. Dispersion V Screen B First C A′ Prism Sample Papers 63

(b) u = – 30 cm, f = 20 cm (i) Using, 1 = 1 – 1 we get, f v u 1 = 1 + 1 = 1 + 1 = 3–2 v f u 20 –30 60 ⇒ v = 60 cm Image is formed at a distance of 60 cm from the lens on the right side. (ii) m ==uv –=6300 – 2 So, image is inverted and double the size of the object. (iii) Image is real as v > 0, inverted and enlarged. 34. (a) (i) Fission (ii) Fragmentation (iii) Regeneration (iv) Budding (b) Amoeba divides by binary fission where the organisms divides equally into two daughter cells. During binary fission, the nuclear division is followed by appearance of a constriction in the cell membrane. Constriction deepens and two cells separate having cytoplasm and nucleus in each cell (daughter cells). Fission Fragmentation It takes place in unicellular organism. It takes place in multicellular organism. Or (a) An organism that reproduces by spores: Rhizopus/ Mucor Advantages: (1) Large number of new individuals are produced at a time. (2) The spores have thick wall which protects them from unfavourable conditions. (b) Functions of: Plumule: Give rise to future shoot or stem of the plant. Radicle: Give rise to future root. Cotyledons: Store food for germinating seed until it bears leaves. 35. (a) (i) Copper will not displace hydrogen from dil. HCl. (ii) Iron will react only with steam to liberate H2(g). 3Fe (s) + 4H2O (g) → Fe3O4 (s) + 4H2(g) (iii) Manganese will react with 5%. HNO3 to give hydrogen. Mn(s) + 2HNO3(5%) → Mg(NO3)2(aq) + H2(g) 64 Together with®  EAD Science—10

(b) (i) Na O (Na)+2 (  O )2– Na (ii) It is due to strong force of attraction between oppositely charged ions. 36. (a) Let I1 and I2 be current flowing through AB, AC and CDE C I2 6W D 4W E respectively. Resistances in the arm CDE are connected in series, B whereas the arms CDE and AB are connected in parallels. A I1 12 W Voltage across two arms is same and is equal to 1.5 V (i) Current in arm AB = VR = 1.5 = 0.125 A 1.5 V 12 Current in arm CDE = VR = 1.5 = 1.5 = 0.15 A (6 + 4) 10 Current in arm AC = Current in arm CDE = 0.15 A (ii) Potential difference across AB = 1.5 V Potential difference across CD = I × R = 0.15 A × 6 W = 0.9 V Potential difference across DE = I × R = 0.15 A × 4 W = 0.6 V (iii) Effective resistance of circuit R1 = 6 W,  R2 = 4 W,  R3 = 12 W, RS = R1 + R2 = 6 + 4 = 10 W,  R3 = 12 W 1 1 1 1 1 6+5 11 R = RS + R3 = 10 + 12 = 60 = 60 R = 60 = 5.4 W 11 (b) Potential difference, V = VA – VB = W Q VA – 10 = 100 = 20 5 VA = 30 V Or (a) The factors on which the resistance of a conductor in the shape of wire depends (i) Length of the conductor: Resistance is directly proportional to length of the conductor. (ii) Area of cross section of the wire: The resistance is inversely proportional to area of cross section of the wire. (iii) The resistance of the conductor depends on the nature of its material. (iv) Temperature of the conductor: Resistance is directly proportional to the temperature of the conductor. (b) Metals are good conductor of electricity as they have free electrons to conduct whereas glass is a bad conductor of electricity as it does not allow electric current to pass through it due to non- availability of free electrons. (c) The alloys are commonly used in electric heating device. This is because (i) Alloy are combination of two or more metals. (ii) Its resistivity is higher than that of its constituent metals. (iii) It neither gets oxidised nor burn easily at high temperature. (iv) It shows less rapid variations of resistivity due to change in temperature. Sample Papers 65