WBCHSE Class 11 Physics Kinetic Theory Of Gases Multiple Choice Questions

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Unit 9 Behavior Of Perfect Gas And Kinetic Theory Chapter 1 Kinetic Theory Of Gases Multiple Choice Questions And Answers

WBBSE Class 11 Kinetic Theory of Gases MCQs

Question 1. If the volume of a body is V1 and the total volume of the molecules of the body is V2, then

  1. V1 = V2
  2. V1 < V2
  3. V1 >V2
  4. V1 < V2 or V1 > V2 for different bodies

Answer: 3. V1 >V2

Question 2. The molecules of all solids

  1. Are relatively closer than those of liquids or gases
  2. Are relatively farther than those of liquids or gases
  3. Move faster than those of liquids or gases
  4. Are stationary as they cannot move inside the solid

Answer: 1. Are relatively closer than those of liquids or gases

Question 3. Which of the following statements is inconsistent with the characteristics of Brownian motion?

  1. The velocity of a particle increases as its size decreases
  2. The velocity of the particles increases as the temperature increases
  3. The velocity of the particles increases as the viscosity of the medium decreases
  4. The velocity of the particles increases when the container is shaken

Answer: 4. The velocity of the particles increases when the container is shaken

Question 4. A piece of wood floating on water does not have any Brownian motion, because

  1. A part of the wooden piece is above the water
  2. The resultant of the applied forces by the water molecules is zero
  3. An adhesive force acts between the molecules of wood and water
  4. The viscosity of water is comparatively less

Answer: 2. The resultant of the applied forces by the water molecules is zero

Question 5. The velocities of two particles moving towards the east are 4 m · s-1 and 6 m · s-1, respectively. The velocities of three other particles moving towards the west are 2 m · s-1, 3 m · s-1, and 5 m · s-1, respectively. The root mean square speed of these 5 particles is

  1. 0
  2. 4m · s-1
  3. 1.667 m · s-1
  4. 4.242 m · s-1

Answer: 4. 4.242 m · s-1

WBCHSE Class 11 Physics Kinetic Theory Of Gases Multiple Choice Questions

Conceptual MCQs on Kinetic Theory for Class 11

Question 6. The pressure and density of hydrogen gas, kept in a vessel, are 1.013 x 106 dyn · cm-2 and 0.089 g · L-1, respectively. The rms speed of the gas molecules will be

  1. 18.5m · s-1
  2. 185m · s-1
  3. 1.85 km · s-1
  4. 18.5 km · s-1

Answer: 3. 1.85 km · s-1

Question 7. If the mean velocity, rms speed, and maximum probable velocity of gas are c, c, and cm, respectively, then

  1. \(c_m<\bar{c}<c\)
  2. \(\bar{c}<c<c_m\)
  3. \(c_m>\bar{c}>c\)
  4. None of these

Answer: 1. \(c_m<\bar{c}<c\)

Question 8. There is a mixture of hydrogen and oxygen gases in a vessel. The root mean square speed of the oxygen molecules is

  1. 4 times that of hydrogen molecules
  2. 16 times that of hydrogen molecules
  3. 1/4 times that of hydrogen molecules
  4. 1/16 times that of hydrogen molecules

Answer: 3. 1/4 times that of hydrogen molecules

Question 9. A mixture of 2 moles of helium gas (atomic mass = 4 amu) and 1 mole of argon gas (atomic mass = 40 amu) is kept at 300 K in a container. The ratio of the rms speeds is

  1. 0.32
  2. 0.45
  3. 2.24
  4. 3.16

Answer: 4. 3.16

Practice Questions on Ideal Gas Behavior

Question 10. At room temperature, the rms speed of the molecules of a certain diatomic gas is found to be 1930 m/s. The gas is

  1. H2
  2. F2
  3. O2
  4. Cl2

Answer: 1. H2

Question 11. If the volume of a container is V, the pressure on the walls of the container by a gas is p and the internal energy of the gas is U, then

  1. U = p V
  2. U = \(\frac{1}{3} p V\)
  3. U = \(\frac{2}{3} p V\)
  4. U = \(\frac{3}{2} p V\)

Answer: 4. U = \(\frac{3}{2} p V\)

Question 12. A certain amount of gas is at 27°C. The rms speed of the gas molecules becomes doubled at

  1. 327°C
  2. 600°C
  3. 927°C
  4. 1200°C

Answer: 3. 1200°C

Question 13. If a gas of a particular mass is expanded at a constant temperature, the variable which undergoes a change is

  1. Pressure of the gas
  2. Internal energy of the gas
  3. Rms speed of the gas molecules
  4. Kinetic energy of the gas molecules

Answer: 1. Pressure of the gas

Key MCQs on Gas Laws and Kinetic Theory

Question 14. At equilibrium conditions, the volume, pressure, and temperature of a gas kept in a closed container are V, p, and T, respectively. If the container is divided into two equal parts by a partition, the value of these quantities for each part will be

  1. \(\frac{V}{2}, \frac{p}{2}, \frac{T}{2}\)
  2. \(\frac{V}{2}, \frac{p}{2}, T\)
  3. \(\frac{V}{2}, p, \frac{T}{2}\)
  4. \(\frac{V}{2}, p, T\)

Answer: 4. \(\frac{V}{2}, p, T\)

Question 15. According to the kinetic theory of gases, there are no intermolecular attractions, so these molecules do not have

  1. Linear momentum
  2. Kinetic energy
  3. Potential energy
  4. Mechanical energy

Answer: 3. Linear momentum

Question 16. If k is Boltzmann constant and T is temperature, the average kinetic energy of each molecule of a gas will be

  1. \(\frac{2}{3} k T\)
  2. \(\sqrt{\frac{2}{3}} k T\)
  3. \(\frac{3}{2} k T\)
  4. \(\sqrt{\frac{3}{2}} k T\)

Answer: 3. \(\frac{3}{2} k T\)

Question 17. The rms speed of oxygen molecules at 47°C will be equal to the rms speed of hydrogen molecules at

  1. 80K
  2. -83K
  3. 3K
  4. 20K

Answer: 4. 20K

WBBSE Class 11 Revision MCQs for Kinetic Theory

Question 18. The pressure, volume, and temperature in two samples of a gas are p, V, T, and 2p,V/4, 2 T, respectively The ratio of the number of molecules in the two samples is

  1. 2:1
  2. 4:1
  3. 8:1
  4. 16:1

Answer: 2. 4:1

Question 19. The rms speed of gas molecules at 0°C will be reduced to half at

  1. 0°C
  2. -273°C
  3. 32°C
  4. -204°C

Answer: 4. -204°C

Question 20. A container of 5 L contains 1026 number of molecules of a gas. If the mass and rms speed of each molecule are 2.4 x 10-25 g and 3.5 x 104 cm · s-1, respectively the pressure of the gas will approximately be

  1. 2 x 106 dyn · cm-2
  2. 106 dyn · cm-2
  3. 3 x 106 dyn · cm-2
  4. 5 x 106 dyn · cm-2

Answer: 1. 2 x 106 dyn · cm-2

Sample Questions on Molecular Speed and Temperature

Question 21. Air is filled in two heat-insulated vessels 1 and 2 having pressure, volume, and temperature p1, V1, T1 and p2, V2, T2 respectively. If the intermediate valve between the two vessels is opened, the temperature of the air at equilibrium will be

  1. \(T_1+T_2\)
  2. \(\frac{T_1 T_2\left(p_1 V_1+p_2 V_2\right)}{p_1 V_1 T_2+p_2 V_2 T_1}\)
  3. \(\frac{T_1+T_2}{2}\)
  4. \(\frac{T_1 T_2\left(p_1 V_1+p_2 V_2\right)}{p_1 V_1 T_1+p_2 V_2 T_2}\)

Answer: 3. \(\frac{T_1+T_2}{2}\)

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Question 22. A vessel contains a mixture of one mole of oxygen and two moles of nitrogen at 300 K. The ratio of the average rotational kinetic energy per O2 molecule to per N2 molecule is

  1. 1:1
  2. 1:2
  3. 2:1
  4. Depends on the moment of inertia of the two molecules

Answer: 1. 1:1

Question 23. 70 cal of heat is required to raise the temperature of 20 moles of an ideal diatomic gas at constant pressure from 30°C. The amount of heat required (in cal) to raise the temperature of the same gas through the same range (30°C to 35°C) at constant volume is

  1. 30
  2. 50
  3. 70
  4. 90

Answer: 2. 50

Question 24. Three closed vessels A, B, and C at the same temperature T contain gases that obey the Maxwellian distribution of velocities. Vessel A contains only O2, B only N2, and C a mixture of equal quantities of O2 and N2. If the average velocity of the O2 molecule in vessel A is v2 and that of the N2 molecule in vessel B is v2, the average velocity of the O2 molecule is vessel C is

  1. \(\frac{\left(v_1+v_2\right)}{2}\)
  2. \(v_1\)
  3. \(\left(v_1 \nu_2\right)^{\frac{1}{2}}\)
  4. \(\sqrt{\frac{3 k T}{M}}\)

Answer: 2. \(v_1\)

WBBSE Class 11 Practice Tests on Kinetic Theory

In this type of question, more than one option are correct

Question 25. From the following statements concerning ideal gas at any given temperature T, select the correct one(s).

  1. The coefficient of volume expansion at constant pressure is the same for all ideal gases
  2. The average translational kinetic energy per molecule of oxygen gas is 3kT, k being the Boltzmann constant
  3. The mean free path of molecules increases with a decrease in pressure
  4. In a gaseous mixture, the average translational kinetic energy of the molecules of each component

Answer:

1. The coefficient of volume expansion at constant pressure is the same for all ideal gases

3. The mean free path of molecules increases with a decrease in pressure

Question 26. Let \(\bar{v}, v_{\mathrm{rms}} \text { and } v_p\) respectively, denote the mean velocity, root mean square speed, and most probable velocity of the molecules in an feed monatomic gas at absolute temperature T. The mass of a molecule is m. Then

  1. No molecule can have a speed greater than \(\sqrt{2} v_{\mathrm{rms}}\)
  2. No molecule can have speed less than \(\frac{v_p}{\sqrt{2}}\)
  3. \(v_p<\bar{v}<v_{\mathrm{rms}}\)
  4. The average kinetic energy of a molecule is \(\frac{3}{4} m v_p^2\)

Answer:

3. \(v_p<\bar{v}<v_{\mathrm{rms}}\)

4. The average kinetic energy of a molecule is \(\frac{3}{4} m v_p^2\)

Question 27. For a jar containing H2 gases which of the following statements are correct?

  1. Both the gas molecules have same average energy
  2. Both the gas molecules have same average translational kinetic energy
  3. Hydrogen molecules have greater average energy than helium molecules
  4. Both the molecules have same average velocity

Answer:

3. Hydrogen molecules have greater average energy than helium molecules

4. Both the molecules have same average velocity

Question 28. The root mean square speed of the perfect gas molecules will be doubled if

  1. Pressure is doubled at constant volume
  2. Pressure is made 4 times at constant volume
  3. Volume is made 4 times at constant pressure
  4. Volume is increased by 41.4% at constant pressure

Answer:

2. Pressure is made 4 times at constant volume

3. Volume is made 4 times at constant pressure

Interactive MCQs on Gas Properties and Kinetic Theory

Question 29. According to the kinetic theory of gases, which of the following statements are true?

  1. Real gas behaves as ideal gas at high temperatures and low pressure
  2. The liquid state of an ideal gas is impossible
  3. At any temperature and pressure, ideal gas obeys Boyle’s law and Charles’ law
  4. The molecules of a real gas do not exert any force on one another

Answer:

  1. Real gas behaves as ideal gas at high temperatures and low pressure
  2. The liquid state of an ideal gas is impossible
  3. At any temperature and pressure, ideal gas obeys Boyle’s law and Charles’ law

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