CBSE Class 10 Science Sample Paper 2012 Set 07

SECTION-A

1. Name the element which has twice as many electrons in its second shell as in its first shell. Write its electronic configuration also.

2. Give common name of the plant on which Mendel performed his experiments.

3. In a food chain comprising frogs, insects, birds and grass, which one of the organisms is likely to have maximum concentration of harmful non biodegradable chemicals in its body?

4. Choose from the following elements whose atomic numbers are given in parentheses

      H(1), He(2), C(6), F(9), Na(11), Cl(17), Mg(12)

    a) Smallest element of 3rd period.

    b) A noble gas.

    c) A metal of 3^rd period having valency 

    d) Most non metallic element of 2^nd period.

5. What is meant by least distance of distinct vision? How does this vary between the very young and old people?

6. a) Distinguish between biodegradable and non biodegradable pollutants.

    b) Choose the bio degradable pollutants from the following. Sewage, DDT, Radioactive waste, Agriculture waste

7. Construction of dams ensures electricity generation for a large number of villages. State two reasons for opposition to the construction of dams in spite of this advantage.

8. a) State two disadvantages of converting forests into mono culture.

    b) Give any two advantages of water stored underground.

    c) State any two measures to conserve wildlife.

9. A student has difficulty in reading the blackboard while sitting in last row. What could be defect of vision? Draw ray diagrams to illustrate this defect and its correction.

10. a) Define power of a lens. What is its unit?

     b) One student uses a lens of focal length 50cm and another of -25cm. What is the nature of lens and its power used by each of them?

11. a) Define absolute refractive index of a medium.

      b) Light travels through glycerine with a speed of 2.05x10⁸m/s. Find the R.I of glycerine.(speed of light in vacuum = 3x10⁸m/s)

12. How is the sex of a new born individual determined genetically in human? 

13. Distinguish between acquired and inherited traits by giving one example each. 

14. What is genetics? State any two factors that could lead to the rise of new species.

15. a) List two advantages of vegetative propagation in plants. 

      b) In which of the following plants is vegetative propagation practiced Banana, Rice, Tomato, Rose

16. List any 2 contraceptive methods practiced only by women. Mention how these methods work.

17. a) How many eggs are produced every month by either of the ovaries in a human female?

      b) Where does fertisation takes place in the female reproductive system?

      c) What happens incase the eggs released by the ovary is not fertilized?

18. a) Which of the following belong to the same homologous series?

      C₂H₆, C₂H₆O₂, C₂H₆O, C₄H₁₀

      b) List two differences between saturated and unsaturated hydrocarbons.

      c) What are isomers?

Please refer to attached file for CBSE Class 10 Science Sample Paper 2012 Set G