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#### Kinetic Theory of Gases Model Question Paper

11th Standard

Reg.No. :
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Physics

Time : 02:00:00 Hrs
Total Marks : 50
5 x 1 = 5
1. A sample of ideal gas is at equilibrium. Which of the following quantity is zero?

(a)

rms speed

(b)

average speed

(c)

average velocity

(d)

most probable speed

2. Two identically sized rooms A and B are connected by an open door. If the room A is air conditioned such that its temperature is 4° lesser than room B, which room has more air in it?

(a)

Room A

(b)

Room B

(c)

Both room has same air

(d)

Cannot be determined

3. The ratio $\gamma =\frac { { C }_{ p } }{ { C }_{ V } }$ for a gas mixture consisting of 8 g of helium and 16 g of oxygen is

(a)

23/15

(b)

15/23

(c)

27/11

(d)

17/27

4. If sP and sV denote the specific heats of nitrogen gas per unit mass at constant pressure and constant volume respectively, then

(a)

sP - sV = 28R

(b)

sP - sV = R/28

(c)

sP - sV = R/14

(d)

sP - sV = R

5. The perfect gas equation can be written as

(a)

PV = $\mu$RT

(b)

PV = $\mu$R

(c)

PV = RT

(d)

P = $\mu$RTV

6. 10 x 2 = 20
7. What is the microscopic origin of pressure?

8. Why moon has no atmosphere?

9. Define the term degrees of freedom.

10. Deduce Charles’ law based on kinetic theory.

11. List the factors affecting the mean free path.

12. A fresh air is composed of nitrogen N2(78%) and oxygen O2(21%). Find the rms speed of N2 and O2 at 20°C.

13. Calculate the temperature at which the rms velocity of a gas triples its value at S.T.P.

14. Calculate the mean free path of air molecules at STP. The diameter of N2 and O2 is about 3 × 10-10 m

15. Estimate the total number of air molecules in a room of capacity 25 m3 at a temperature of 27°C.

16. What type of motion is associated with the molecule of a gas?

17. 5 x 3 = 15
18. Write down the postulates of kinetic theory of gases.

19. Explain in detail the kinetic interpretation of temperature.

20. Explain in detail the Maxwell Boltzmann distribution function.

21. Describe the Brownian motion.

22. State and explain Boyle's law.

23. 2 x 5 = 10
24. Calculate the rms speed, average speed and the most probable speed of 1 mole of hydrogen molecules at 300 K. Neglect the mass of electron.

25. An oxygen molecule is travelling in air at 300 K and 1 atm, and the diameter of oxygen molecule is 1.2 × 10−10m. Calculate the mean free path of oxygen molecule.