Section-A

1 Science X Sample Paper 10 Solved CLASS X (2020-21). SCIENCE (CODE 086). SAMPLE PAPER-10. Time : 3 Hours 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.

2 (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 labelled diagrams should be drawn. human beings? How is it removed from the body? Section-A Ans : 1. What is a chemical equation? [1] The major nitrogenous waste product in human Ans : beings is urea.

3 Urea is removed/ eliminated from the body through urine. A chemical equation is a representation of chemical change in terms of symbols and formulae of reactants 6. Why does lack of oxygen in muscles often lead to and products. cramps among cricketers? [1]. o Ans : Balance the following chemical equation: This is due to the conversion of pyruvate to lactic acid Ans : in the absence of oxygen. Heat 7. Write two different uses of concave mirrors. [1]. 2Pb (NO 3) 2 (s) 2 PbO (s) + 4NO 2 (g) + O 2 (g). Ans : 2. What is a neutralisation reaction? [1]. Concave mirrors are used in (a) torches, (b). Ans : searchlights, (c) headlights of vehicles, etc. The reaction between acid and base to form salt and o water is called neutralisation reaction.

4 Define the term magnification. 3. Define allotropy. [1] Ans : Ans : The ratio of the height of image to the height of object Allotropy is the property of an element to exist in is called magnification. different physical forms but have similar chemical 8. Draw a labelled ray diagram to show the path of the properties. reflected ray corresponding to an incident ray of light 4. In which forms do most plants absorb nitrogen? [1] parallel to the principal axis of a convex mirror. Mark Ans : the angle of incidence and angle of reflection on it. [1]. Nitrates and nitrites. Ans : 5. What is ascent of sap? [1]. Ans : Absorbed water from the soil contains dissolved minerals (nitrates, phosphates, etc.)

5 And hence it is called sap. This sap moves upwards due to the transpiration pull' developed in the xylem elements. Thus, transportation of sap from roots to the leaves at the top is called ascent of sap. o Which is the major nitrogenous waste product in Download 20 Solved Sample Papers pdf from Page 1. Science X Sample Paper 10 Solved 9. Why do we see a rainbow in the sky only after 14. Assertion : Calcium carbonate when heated gives rainfall? [1] calcium oxide and water. Ans : Reason : On heating calcium carbonate, decomposition reaction takes place. [1]. Rainbow is caused by dispersion of sunlight by tiny water droplets, present in the atmosphere. The water Ans : (d) A is false but R is true.

6 Droplets behave like prisms and disperse sunlight. 15. Assertion : Mutation is sudden change in the genetic 10. Mention the condition under which a current can flow material. in a conductor. [1] Reason : Variation is useful for the survival of species Ans : over time. [1]. The condition under which a current can flow in a Ans : (b) Both A and R are true but R is not the conductor is that the circuit is closed and there is a correct explanation of the assertion. potential difference across the conductor. 16. Assertion : Man is a herbivore. o Reason : Omnivores eat both plant parts and meat of What are the special features of a heating wire? animals. [1]. Ans : Ans : (d) A is false but R is true.

7 It must have high specific resistance and high melting o point. Assertion : The food in the ecosystem is preserved in 11. On what effect of an electric current does an a linear fashion. electromagnet work? [1] Reason : Plants use the solar energy in reducing Ans : carbon dioxide to carbon. An electromagnet works on the principle of magnetic Ans : (b) Both A and R are true but R is not the effect of current. correct explanation of the assertion. 12. State Faraday's law of electromagnetic induction. [1] 17. Read the following and answer any four questions Ans : from to 1#4. In Modern Periodic Table, metals are towards the Whenever the magnetic field lines linked with a coil left hand side, non-metals are towards the right hand change due to relative motion of a magnet and the side and there is a zig-zag line between them which coil, an induced current is produced in the coil.

8 The contains metalloids. magnitude of induced current is directly proportional Metals are electropositive, , they have a tendency to the rate of change of number of magnetic field lines to lose electrons. As the effective nuclear charge acting linked to the coil. on the valence shell electrons increases across a period, 13. Which of the following are always at the second the tendency to lose electron will decrease so metallic trophic level of food chains? character decreases. Down the group, the effective Carnivores, Autotrophs, Herbivores [1] nuclear charge experienced by valence electrons is Ans : decreasing because the outermost electrons are farther away from the nucleus.

9 Therefore, they can be lost Herbivores are always at the second trophic level of easily and thus metallic character increases down the food chains. group. o Non-metals on the other hand, are electronegative. What will be the amount of energy available to the They tend to form bonds by gaining electrons. organisms of the 2nd trophic level of a food chain, if Non-metallic character increases along the period and the energy available at the first trophic level is 10,000 decreases down the group. joules? of the following element is not a metalloid? Ans : (a) Ge On applying the 10% law to the food chain, the (b) As organisms of the 2nd trophic level of the food chain (c) Ar will have 10 # 10, 000 = 1000 joules of energy.

10 (d) Te 100. Ans : (c) Ar For question numbers 14, 15 and 16, two statements are given-one labelled Assertion (A) and the other Ar is a non-metal. labelled Reason (R). Select the correct answer to order of metallic character of some elements is these questions from the codes (a), (b), (c) and (d) as N < P < As < Sb < Bi. The most electronegative given below : among these elements is (a) N. (a) Both A and R are true and R is correct explanation (b) P. of the assertion. (c) Sb (b) Both A and R are true but R is not the correct explanation of the assertion. (d) Bi (c) A is true but R is false. Ans : (a) N. (d) A is false but R is true. Electronegativity decreases down the group.