Objective Type Questions & Answers On Class 11 Physics Chapter 13 Kinetic Theory

1 When an ideal gas is compressed adiabatically, its temperature rises: the molecules on the average have more kinetic energy than before. The kinetic energy increases,

A because of collisions with moving parts of the wall only

B because of collisions with the entire wall

C because the molecules gets accelerated in their motion inside the volume

D because of the redistribution of energy amongst the molecules

View Answer

Answer:because of collisions with moving parts of the wall only

2 Ina diatomic molecules, the rotational energy at a given temperature

A obeys Maxwell’s distribution

B have the same value for all molecules

C equals the translational kinetic energy for each molecule

D is 2/3rd the translational kinetic energy for each molecule

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Answer:A, D

3 Diatomic molecules like hydrogen have energies due to both translational as well as rotational motion. From the equation in kinetic theory pV = 2/3 E, E is

A the total energy per unit volume

B only the translational part of energy because rotational energy is very small compared to the translational energy

C only the translational part of the energy because during collisions with the wall pressure relates to change in linear momentum

D the translational part of the energy because rotational energies of molecules can be either sign and its average over all the molecules is zero

View Answer

Answer:only the translational part of the energy because during collisions with the wall pressure relates to change in linear momentum

4 ABCDEFGH is a hollow cube made of an insulator. Face ABCD has a positive charge on it. Inside the cube, we have ionized hydrogen. The usual kinetic theory expression for pressure

Kinectic Energy

A will be valid

B will not be valid since the ions would experience forces other than due to collision with the walls

C will not be valid since collisions with walls would not be elastic

D will not be valid because isotropy is lost

View Answer

Answer:B, D

5 An inflated rubber balloon contains one mole of an ideal gas, has a pressure p, volume V, and temperature T. If the temperature rises to 1.1T and the volume is increased to 1.05V, the final pressure will be

A 1.1 p

B p

C less than p

D between p and 1.1

View Answer

Answer:between p and 1.1

6 A vessel of volume V contains a mixture of 1 mole of hydrogen and 1 mole of oxygen. Let f₁(v)dv, denote the fraction of molecules with speed between v and (v + dv) with f₂(v)dv similarly for oxygen. Then

A f₁(v) + f₂(v) = f(v) obeys the Maxwell’s distribution law

B f₁(v), f₂(v) will obey the Maxwell’s distribution law separately

C neither f₁(v) nor f₂(v) will obey the Maxwell’s distribution law

D f₂(v) and f₁(v) will be the same

View Answer

Answer:f1(v), f2(v) will obey the Maxwell’s distribution law separately

7 1 mole of H2 gas is contained in a box of volume V = 1.00 m3 at T = 300 K. The gas is heated to a temperature of T = 3000 K and the gas gets converted to a gas of hydrogen atoms. The final pressure would be

A same as the pressure initially

B 2 times the pressure initially

C 10 times the pressure initially

D 20 times the pressure initially

View Answer

Answer:20 times the pressure initially

8 Volume versus temperature graphs for a given mass of an ideal gas are shown in the figure at two different values of constant pressure. What can be inferred about the relation between P₁ and P₂?

Kinetic Theory

A P₁ > P₂

B P₁ = P₂

C P₁ < P₂

D data is insufficient

View Answer

Answer:P₁ > P₂

9 Boyle’s law is applicable for an

A adiabatic process

B isothermal process

C isobaric process

D isochoric process

View Answer

Answer:isothermal process

10 1 mole of an ideal gas is contained in a cubical volume V, ABCDEFGH at 300 K. One face of the cube (EFGH) is made up of a material which totally absorbs any gas molecule incident on it. At any given time,

Kinetic Theory

A the pressure on EFGH would be zero

B the pressure on all the faces will the equal

C the pressure of EFGH would be double the pressure on ABCD

D the pressure on EFGH would be half that on ABCD

View Answer

Answer:the pressure on EFGH would be half that on ABCD

11 A container has a mixture of 1 mole of oxygen and 2 moles of nitrogen at 330K.The ratio of average rotational kinetic energy per O₂ molecule to that per H₂ molecule is

A 2:1

B 1:2

C 1:1

D None of these

View Answer

Answer:1:1

12 There are two statement about Ideal gases

Statement A The Vrms of gas molecules depends on the mass of the gas molecule and the temperature

Statement B The Vrms is same for all the gases at the same temperature which one of the following is correct

A A and B both

B A only

C B only

D A and B both are incorrect

View Answer

Answer:A only

13 There are two statement

Statement A. Equal volumes of all gases at the same temperature T and pressure P contain an equal no of Molecules

Statement B,.the no of molecules in one mole of any gas is 6.0255 * 10²².
which one of the following is correct

A A and B both

B A only

C B only

D A and B both are incorrect

View Answer

Answer:A and B both

14 M moles of a ideal polyatomic gas(C_v=7R/2) are in cylinder at temperature T.A heat Q is supplied to the gas. Some M/3 moles of the gas dissociated into atoms while temperature remains constant. Find the correct relation

A 3Q=4MRT

B 2Q=3MRT

C Q=4MRT

D 7Q=4MRT

View Answer

Answer:3Q=4MRT

15 The prefect gases A, B & C having masses m₁, m₂& m₃ at temperature T₁, T₂ & T₃ are mixed without any loses of internal energy of the molecules. The molecules weight of the gases is M₁, M₂, M₃ what is the final temperature of mixture.

A [(m₁/M₁)T₁ + (m₂/M₂)T₂ + (m₃/M₃)T₃]/(m₁/M₁+m₂/M₂+m₃/M₃)

B [(M₁/m₁)T₁ + (M₂/m₂)T₂ + (M₃/m₃)T₃]/(M₁/m₁+M₂/m₂+M₃/m₃)

C [(m₁)T₁ + (m₂)T₂ +(m₃)T₃]/(m₁+m₂+m₃)

D [(M₁)T₁ + (M₂)T₂ + (M₃)T₃]/(M₁+M₂+M₃)

View Answer

Answer:[(m₁/M₁)T₁ + (m₂/M₂)T₂ + (m₃/M₃)T₃]/(m₁/M₁+m₂/M₂+m₃/M₃)

16 Equal Number of molecules of hydrogen & Oxygen are contained in a vessel at one atmosphere pressure. The ratio of the collision frequency of hydrogen molecules to the of Oxygen molecules on the container

A 1:4

B 4:1

C 1:16

D 16:1

View Answer

Answer:4:1

17 The velocities of the molecules are v, 2v, 3v, 4v & 5v. The rms speed will be

A 11v

B v(11)^1/2

C v

D 3.3v

View Answer

Answer:v(11)^1/2

18 Suppose a container is evacuated to have just one molecule of a gas in it. Let V_a & V_rms represent the Average Speed and rms speed of the molecule

A V_a > V_rms

B V_a < V_rms

C V_a = V_rms

D V_rms is undefined

View Answer

Answer:V_a = V_rms

19 Find the ratio of mean speed of Oxygen, chlorine, Hydrogen

A 4:1 : (.45)^1/2

B 5:2 :(5)^1/2

C 1: (.45)^1/2:4

D 2 :(.45)^1/2 : (1.5)^1/2

View Answer

Answer:1: (.45)^1/2:4

20 Let V, V_rms and V_p respectively denotes the mean speed, root mean square speed and most probable speed of the molecule in ideal monatomic gas at absolute temperature T. The mass of the molecule
is m then

A No molecule can have a speed greater the (2)^1/2V_rms

B No molecule can have a speed less the V_p / (2)^1/2

C V_p < V < V_rms

D The average kinetic charge of a molecule (3/4 )mV_p²

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