Question

1. When an object moves on a circular path, what is the work done?
2. Write the unit of work?
3. What is the term given to increase in annual earth’s temperature?
4. What is the percentage of nitrogen and oxygen in the air?
5. Give one achievement and one limitation of Thomson’s model.
6. (a) Hydrogen and oxygen combine in the ratio of 1:8 by mass to form water. What mass of oxygen gas
would be required to react completely with 3 g of hydrogen gas?
(b)Write the molecular formula of a diatomic gas and a triatomic gas.

7. (a) Identify any two features possessed by Chordates.
(b) In which class would you place an organism which has:
(i) A scaly exoskeleton and a bony endoskeleton.
(ii) A scaly exoskeleton and lay eggs outside water.
8. (a) Write two points of difference between amphibians and reptiles.
(b) List two characters which help amphibians to survive on land.
10. (i) Do fluids exert pressure? How is pressure transmitted in a fluid?
(ii) Why a steel ball sinks in water? 10. Relative density of silver is 10.8. The density of water is 103
Kgm-3 . What is the density of silver in SI unit?
11. (i) Give any two examples of longitudinal waves.
(ii) What is the most essential property of a wave motion and why?
12. (a) What is the major component of atmosphere of earth and Venus?

Answer 1

Answer:

1) zero

2)Joule

3)global warming

4)78% of nitigen and 21% of oxygen

5)achievement:It explained the stability and neutrility of the atom

limitation:It was unable to explain the scattering experiment of Rutherford.

6)a. 24g of oxygen/3g of hydrogen

b.O2 -oxygen

O3-ozone

7)a. a notochord and a dorsal hollow nerve cord

b.a.mammals

b.reptiles