Class 10 Science Sample Paper (Our Environment, Chemical reaction and equation, Acid base and salt, Electricity, Preodic table, Reproduction, Life process, Carbon and it's Compound)

1. (a) What is ‘environmental pollution? (b) Distinguish between biodegradable and non-biodegradable pollutants. (c) Choose the biodegradable pollutants from the list given below: Sewage, DDT, radioactive waste, agricultural waste. (3 Marks)
2. Why is ozone layer getting depleted at the higher levels of the atmosphere? (1Marks)

3. Name any two abiotic components of an environment. (1Marks)
4. Why green plants are called ‘producers’? (1Marks)
5. Explain ‘biological magnification’ with the help of an example. (2 Marks)
6. Define ‘trophic level’ (1 Marks)
7. What is the role of decomposers in the ecosystem? (1Marks)
8. State Ohm’s law. Write the necessary conditions for its validity. How is this law verified experimentally? What will be the nature of graph between potential difference and current for a conductor? Name the physical quantity that can be obtained from this graph. (5 Marks)
9. The charge possessed by an electron is 1.6 X 10^-19 coulombs. Find the number of electrons that will flow per second to constitute a current of 1 ampere. (2 Marks)
10. Series arrangements are not used for domestic circuits. List any three reasons (3 Marks)
11. Identify the oxidising agent (oxidant) in the following reactions (5 Marks)
(a) Pb3O4 + 8HCl → 3PbCl₂ + Cl₂ + 4H₂O
(b) 2Mg + O₂ → 2MgO
(c) CuSO₄ + Zn → Cu + ZnSO₄
(d) V₂O₅ + 5Ca → 2V + 5CaO
(e) 3Fe + 4H₂O → Fe₃O₄ + 4H₂
12. State reason for the following statements: ( 5 Marks)

(i) Tap water conducts electricity whereas distilled water does not. (ii) Dry hydrogen chloride gas does not turn blue litmus red whereas dilute hydrochloric acid does. (iii) During summer season, a milk man usually adds a very small amount of baking soda to fresh milk. (iv) For a dilution of acid, acid is added into water and not water into acid. (v) Ammonia is a base but does not contain hydroxyl group.
13. Which of the following substance will not give carbon dioxide on treatment with dilute acid?
(a) Marble (b) Limestone (c) Baking soda (d) Lime (1 Marks)
14. Buckminsterfullerene is an allotropic form of (a) phosphorus (b) sulphur (c) carbon (d) tin ( 1Marks)
15. Upto which element, the Law of Octaves was found to be applicable
(a) Oxygen (b) Calcium (c) Cobalt (d) Potassium (1Marks)
16. Which one of the following elements exhibit maximum number of valence electrons?
(a) Na (b) Al (c) Si (d) P (1 Marks)
17. Which part of alimentary canal receives bile from the liver?
 (a) Stomach (b) Small intestine (c) Large intestine (d) Oesophagus (1Marks)
18. Characters transmitted from parents to offspring are present in
 (a) cytoplasm (b) ribosome(c) golgi bodies(d) genes (1Marks)
19. In which part of the alimentary canal food is finally digested?
 (a) Stomach (b) Mouth cavity (c) Large intestine (d) Small intestine (1Marks)
20. The filtration units of kidneys are called (a) ureter (b) urethra (c) neurons (d) nephrons (1Marks)
21. In human females, an event that reflects onset of reproductive phase is
(a) growth of body (b) changes in hair pattern (c) change in voice (d) menstruation (1 Marks)
22. In human males, the testes lie in the scrotum, because it helps in the
 (a) process of mating (b) formation of sperm (c) easy transfer of gametes (d) all the above (1Marks)