#### 11th Standard Physics Kinetic Theory of Gases English Medium Free Online Test One Mark Questions with Answer Key 2020 - 2021

11th Standard

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Physics

Time : 00:20:00 Hrs
Total Marks : 20

20 x 1 = 20
1. An ideal gas is maintained at constant pressure. If the temperature of an ideal gas increases from 100K to 1000K then the rms speed of the gas molecules

(a)

increases by 5 times

(b)

increases by 10 times

(c)

remains same

(d)

increases by 7 times

2. The average translational kinetic energy of gas molecules depends on

(a)

number of moles and T

(b)

only on T

(c)

P and T

(d)

P only

3. A container has one mole of monoatomic ideal gas. Each molecule has f degrees of freedom. What is the ratio of $\gamma =\frac { { C }_{ p } }{ { C }_{ V } }$

(a)

f

(b)

$\frac{f}{2}$

(c)

$\frac{f}{f+2}$

(d)

$\frac{f+2}{f}$

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. For a given gas molecule at a fixed temperature, the area under the Maxwell-Boltzmann distribution curve is equal to

(a)

$\frac{PV}{KT}$

(b)

$\frac{KT}{PV}$

(c)

$\frac{P}{NKT}$

(d)

PV

6. Kinetic theory ___________.

(a)

Correctly explains specific heat capacities of many liquid

(b)

Correctly explains specific heat capacities of many gases

(c)

Correctly explains specific heat capacities of many solids

(d)

Correctly explains specific heat capacities of many super cooled liquid

7. According to Dalton's law of partial pressures ______________

(a)

total pressure of a mixture of real gases is the sum of factored in - virtual pressure

(b)

total pressure of a mixture of ideal gases is the difference partial pressure

(c)

total pressure of a mixture of real gases is the sum of pressures

(d)

total pressure of a mixture of real gases is the sum of partial pressure

8. The average K.E of a molecule __________.

(a)

is inversely proportional to the molecular mass of the gas.

(b)

is inversely proportional to the absolute temperature mass of the gas.

(c)

is directly proportional to the absolute temperature mass of the gas.

(d)

is not dependent on absolute temperature of the gas.

9. The gas having average speed four times as that of SO2 (molecule mass 64) is ____________.

(a)

He (molecule mass 64)

(b)

O2 (molecule mass 4)

(c)

M2 (molecule mass 32)

(d)

CH4 (molecule mass 16)

10. In an adiabatic change, the pressure and temperature of a mono - atomic gas are related as p$\times$TC, where C equals ____________.

(a)

$\frac{2}{5}$

(b)

$\frac{5}{2}$

(c)

$\frac{3}{5}$

(d)

$\frac{5}{3}$

11. The slope at any point on the curve in PV graph for a gas is gn involving the reaction _______________.

(a)

$\frac { dp }{ p } =\frac { dV }{ V }$

(b)

$\frac { dp }{ V } =-\frac { dV }{ P }$

(c)

$\frac { dp }{ p } =\frac { dV }{ V }$

(d)

$\frac { dp }{ V } =\frac { dV }{ P }$

12. According to the kinetic theory of gases ____________.

(a)

the pressure of a gas is proportional to the rms speed of the molecules

(b)

the rms speed of the molecules of a gas is proportional to the absolute temperature

(c)

the rms speed of the molecules of a gas is proportional to the square root of the absolute temperature

(d)

the pressure of a gas is proportional to the square root of the rms speed of the molecules

13. The temperature of an ideal gas is increased from 27°C to 927°C. The root mean square speed of its molecules becomes ________________.

(a)

3 times

(b)

double

(c)

4 times

(d)

6 times

14. If the absolute temperature of a gas is increased 3 times the rms velocity of the molecules will be _________.

(a)

3 times

(b)

9 times

(c)

$\sqrt 3$ times

(d)

$\sqrt 6$ times

15. Two vessels have equal volumes. One of them contains hydrogen at one atmosphere and the other helium at two atmospheres. If both the samples are at the same temperature, the rms velocity of the hydrogen molecules is _________.

(a)

equal to that of the helium molecules

(b)

twice that of the helium molecules

(c)

half that of the helium molecules

(d)

$\sqrt 2$ times that of the helium molecules

16. The mean translational K.E. of a perfect gas molecule at absolute temperature T is _____________ (K is Boltzmann constant)

(a)

$\frac{1}{2}$kT

(b)

kT

(c)

$\frac{3}{2}$kT

(d)

$\frac{5}{2}$kT

17. The pressure exerted on the walls of the container by a gas is due to the fact that the gas molecules _________.

(a)

lose their K.E

(b)

Stick to the walls

(c)

are accelerated towards the walls

(d)

change their momenta due to collision with the walls.

18. The kinetic theory of gases breaks down most at _________.

(a)

low pressure and high temperature

(b)

high pressure and low temperature

(c)

low pressure and low temperature

(d)

high pressure and high temperature

19. A cylinder of capacity 20 litres is filled with hydrogen gas. The total average K.E. of translatory motion of its molecules is 1.5$\times$105 J. The pressure of hydrogen in the cylinder is ________.

(a)

2$\times$106Nm-2

(b)

3$\times$106Nm-2

(c)

4$\times$106Nm-2

(d)

5$\times$106Nm-2

20. The average energy of a molecules of a mono atomic gas at temperature T is _____________ (K = Boltzmann constant).

(a)

$\frac{1}{2}$kT

(b)

kT

(c)

$\frac{3}{2}$kT

(d)

$\frac{5}{2}$kT