Unsolved Worksheet 1

 Unsolved Worksheet 1

1. Write the number of Covalent bonds in the molecule of ethane.

2. Name the life process of an organism that helps in the growth of its population.

3. What will be the amount of energy available to the organisms of the second trophic level of a food chain, if the energy available at the first trophic level is 10,000 joules ?

4. The absolute refractive indices of glass and water are 4/3 and 3/2 respectively. If the speed of light in glass in 2×10⁸ m/s, Calculate the speed of light in (i) vacuum,  (ii) Water.

5. List two tests for experimentally distinguishing between an alcohol and a carboxylic acid and describe how these tests pre performed.

6. Draw the electron dot structure for ethyne. A mixture of ethyne and oxygen is burnt for welding. In your opinion, why cannot we use a mixture of ethyne and air for this purpose?

7. List six specific characteristics of sexual reproduction.

8. What are chromosomes? Explain how in sexually reproducing organisms the number of chromosomes in the progeny is maintained.

9. List four points of significance of reproductive health in a society. Name any two areas related to reproductive health which have improved over the past 50 years in our country.

10. If the image formed by a mirror for all positions of objects placed in front of it is always erect and diminished, what type of mirror is it? Draw a ray diagram to justify your answer. Where and why do we generally use this type of mirror?

11. What is meant by scattering of light? Use this phenomenon to explain why the clear sky appears blue.

12. Both soap and detergent are some type of salts. What is the difference between them ? Describe in brief the cleansing action of soap. Why do soaps not form lather in hard water? List two problem that arise due to the use of detergents instead of soaps.

13. Name the human male reproductive organ that produces sperms and also secretes a hormone. Write the functions of the secreted hormone.

Name the parts of the human female reproductive system where:

(i) fertilisation takes places

(ii) implantation of the fertilised egg occurs.

14. How do Mendel's experiments show that the 

(a) traits may be dominant or recessive.

(b) traits are inherited independently?

15. What is meant by power of a lens? Define its SI unit.

Your have two lenses A and B of focal lengths +10 cm and -10 cm respectively. State the nature and power of each lens. Which of the two lenses will form a virtual and magnified image of an object placed 8 cm from the lens? Draw a ray diagram to justify your answer.