CBSE Class 11 Physics Kinetic Theory Worksheet Set A

Question- When do real gases approach the ideal gas behaviour ?

(a) At low pressure and low temperature

(b) At low pressure and high temperature

(c) At high pressure and high temperature

(d) At high pressure and low temperature

Answer-(b)

Question-The internal energy of a gram-molecule of an ideal gas depends on

(a) pressure alone

(b) volume alone

(c) temperature alone

(d) both on pressure as well as temperature

Answer-(a)

Question-According to kinetic theory of matter, a molecule is the smallest particle of a substance and it possesses

(a) all the properties of the substance

(b) some of the properties of the substance

(c) none of the properties of the substance

(d) either (b) or (c)

Answer-(a)

Question- Kinetic theory of gases provide a base for

(a) Charle’s law

(b) Boyle’s law

(c) Both Charle’s law and Boyle’s law

(d) None of these

Answer-(c)

Question-The pressure exerted on the walls of container by a gas is due to the fact that gas molecules are

(a) losing their kinetic energy

(b) sticking to the walls

(c) changing their momenta due to collision with the walls

(d) getting accelerated towards the wall

Answer-(c)

Question-The temperature of gas is produced by

(a) the potential energy of its molecules

(b) the kinetic energy of its molecules

(c) the attractive force between its molecules

(d) the repulsive force between its molecules

Answer-(b)

Question-The temperature of a gas is a measure of

(a) the average kinetic energy of the gaseous molecules

(b) the average potential energy of the gaseous molecules

(c) the average distance between the molecules of the gas

(d) the size of the molecules of the gas

Answer-(a)

Question-The absolute temperature of a gas determines

(a) the average momentum of the molecule

(b) the velocity of sound in the gas

(c) the number of molecules in the gas

(d) the mean square velocity of the molecules

Answer-(d)

Question-At a given temperature the force between molecules of a gas as a function of intermolecular distance is

(a) always constant

(b) always decreases

(c) always increases

(d) first decreases and then increases

Answer-(d)

Question-In kinetic theory of gases, it is assumed that molecules

(a) have same mass but can have different volume

(b) have same volume but mass can be different

(c) have different mass as well as volume

(d) have same mass but negligible volume.

Answer-(d)

Question-The phenomenon of Browninan movement may be taken as evidence of

(a) kinetic theory of matter

(b) electromagnetic theory of radiation

(c) corpuscular theory of light

(d) photoelectric phenomenon

Answer-(a)

Question-According to the kinetic theory of gases, the pressure exerted by a gas on the wall of the container is measured as

(a) rate of change of momentum imparted to the walls per second per unit area.

(b) momentum imparted to the walls per unit area

(c) change of momentum imparted to the walls per unit area.

(d) change in momentum per unit volume

Answer-(a)

Question-At 0K which of the following of a gas will be zero?

(a) Kinetic energy

(b) Potential energy

(c) Vibrational energy

(d) Density

Answer-(a)

Question-When a gas is in thermal equilibrium, its molecules

(a) have the same average kinetic energy of molecules

(b) have different energies which remain constant

(c) have a certain constant energy

(d) do not collide with one another

Answer-(a)

Question-According to kinetic theory of gases, at absolute zero temperature

(a) water freezes

(b) liquid helium freezes

(c) molecular motion stops

(d) liquid hydrogen freezes

Answer-(c)

Question- Which of the following molecular properties is the same for all ideal gases at a given temperature

(a) momentum

(b) rms velocity

(c) mean kinetic energy

(d) mean free path

Answer-(c)

Question- When do real gases approach the ideal gas behaviour ?

(a) At low pressure and low temperature

(b) At low pressure and high temperature

(c) At high pressure and high temperature

(d) At high pressure and low temperature

Answer-(b)

Question- A fly moving in a room has ...X... degree of freedom. Here, X refers to

(a) one

(b) two

(c) three

(d) four

Answer-(c)

Question- The equation which should be satisfied exactly at all pressures and temperatures to be an ideal gas is

(a) PV = μRT

(b) PV = k_BNT

(c) P = k_B nT.

(d) All of these

Answer-(c)

Question- At a given temperature which of the following gases possesses maximum r.m.s. velocity?

(a) Hydrogen

(b) Oxygen

(c) Nitrogen

(d) Carbon dioxide

Answer-(a)

Question- In a mixture of gases at a fixed temperature

(a) heavier molecule has higher average speed

(b) lighter molecule has lower average speed

(c) heavier molecule has lower average speed

(d) None of these

Answer-(c)

Question- Boyle' law is applicable for an

(a) adiabatic process.

(b) isothermal process.

(c) isobaric process.

(d) isochoric process

Answer-(b)

Question- The average kinetic energy of gas molecules depends upon which of the following factor?

(a) Nature of the gas

(b) Temperature of the gas

(c) Volume of the gas

(d) Both (b) & (c)

Answer-(b)

Question- The total number of degree of freedom of a CO₂ gas molecule is

(a) 3

(b) 6

(c) 5

(d) 4

Answer-(c)

Question- Cooking gas containers are kept in a lorry moving with uniform speed. The temperature of the gas molecules inside will.

(a) increase

(b) decrease

(c) remains the same

(d) decrease for some and increase for others

Answer-(c)

Question- In the kinetic theory of gases, which of these statements is/are true ?
I. The pressure of a gas is proportional to the mean speed of the molecules.
II. The root mean square speed of the molecules is proportional to the pressure.
III. The rate of diffusion is proportional to the mean speed of the molecules.
IV. The mean translational kinetic energy of a gas is proportional to its kelvin temperature.

(a) II and III only

(b) I, II and IV

(c) I and III only

(d) III and IV only

Answer-(d)

Question- If the pressure and the volume of certain quantity of ideal gas are halved, then its temperature

(a) is doubled

(b) becomes one-fourth

(c) remains constant

(d) is halved

Answer-(b)

Question- Maxwell's laws of distribution of velocities shows that

(a) the number of molecules with most probable velocity is very large

(b) the number of molecules with most probable velocity is very small

(c) the number of molecules with most probable velocity is zero

(d) the number of molecules with most probable velocity is exactly equal to 1

Answer-(a)

Question- Pressure exerted by a gas is

(a) independent of density of the gas

(b) inversely proportional to the density of the gas

(c) directly proportional to the square of the density of the gas

(d) directly proportional to the density of the gas

Answer-(d)

Question-  According to the kinetic theory of gases, the r.m.s. velocity of gas molecules is directly proportional to

(a) T

(b) √T

(c) T²

(d) 1/ √T

Answer-(b)

Question- The relation PV = RT can describe the behaviour of a real gas at

(a) high temperature and high pressure

(b) high temperature and low pressure

(c) low temperature and low pressure

(d) low temperature and high pressure

Answer-(b)

Question- For Boyle’s law to hold, the gas should be

(a) perfect and of constant mass and temperature

(b) real and of constant mass and temperature

(c) perfect and constant temperature but variable mass

(d) real and constant temperature but variable mass

Answer-(a)

Question- The deviation of gases from the behaviour of ideal gas is due to

(a) colourless molecules

(b) covalent bonding of molecules

(c) attraction of molecules

(d) absolute scale of temp.

Answer-(c)

Question- From the following statements, concerning ideal gas at any given temperature T, select the correct one(s)
I. The coefficient of volume expansion at constant pressure is same for all ideal gas
II. The average translational kinetic energy per molecule of oxygen gas is 3 KT (K being Boltzmann constant)
III. In a gaseous mixture, the average translational kinetic energy of the molecules of each component is same
IV. The mean free path of molecules increases with decrease in pressure

(a) I, II and III

(b) III and IV only

(c) I, III and IV

(d) I, II, III and IV

Answer-(c)

Question- In Boyle’s law what remains constant ?

(a) PV

(b) TV

(c) V/T

(d) P/T

Answer-(a)

Question- The ratio of the molar heat capacities of a diatomic gas at constant pressure to that a constant volume is

(a) 7/2

(b) 3/2

(c) 3/5

(d) 7/5

Answer-(d)

Question- When temperature is constant, the pressure of a given mass of gas varies inversely with volume. This is the statement of

(a) Boyle’s law

(b) Charle’s law

(c) Avogadro’s law

d) None of these

Answer-(a)

Question- The average kinetic energy of a molecule of a perfect gas is

(a) (2/3) k T

(b) 1.5 k T

(c) 2.5 k T

(d) None of these

Answer-(b)

Question- In kinetic theory of gases, one assumes that the collisions between the molecules are

(a) perfectly elastic

(b) perfectly inelastic

(c) partly inelastic

(d) may be perfectly elastic or perfectly inelastic depending on nature of gas

Answer-(a)

Question- The specific heat of a gas

(a) has only two values c_p and c_v

(b) has a unique value at a given temperature

(c) can have any value between 0 and ∞

(d) depends upon the mass of the gas

Answer-(c)

Question- The specific heats at constant pressure is greater than that of the same gas at constant volume because

(a) at constant pressure work is done in expanding the gas

(b) at constant volume work is done in expanding the gas

(c) the molecular attraction increases more at constant pressure

(d) the molecular vibration increases more at constant pressure

Answer-(a)

Question- As per the law of equi-partition of energy each vibrational mode gives how many degrees of freedom ?

(a) 1

(b) 2

(c) 3

(d) 0

Answer-(b)

Question- Molecules of a ideal gas behave like

(a) inelastic rigid sphere

(b) perfectly elastic non-rigid sphere

(c) perfectly elastic rigid sphere

(d) inelastic non-rigid sphere

Answer-(c)

Question-  At constant volume, temperature is increased then

(a) collision on walls will be less

(b) number of collisions per unit time will increase

(c) collisions will be in straight lines

(d) collisions will not change.

Answer-(b)

Question- The number of degrees of freedom for each atom of a monatomic gas is

(a) 3

(b) 5

(c) 6

(d) 1

Answer-(a)

Question- The degree of freedom of a molecule of a triatomic gas is

(a) 2

(b) 4

(c) 6

(d) 8

Answer-(c)

Question- Mean free path of a gas molecule is

(a) inversely proportional to number of molecules per unit volume

(b) inversely proportional to diameter of the molecule

(c) directly proportional to the square root of the absolute temperature

(d) directly proportional to the molecular mass

Answer-(a)

Question-  If a gas is heated at constant pressure, its isothermal compressibility

(a) remains constant

(b) increases linearly with temperature

(c) decreases linearly with temperature

(d) decreases inversely with temperature

Answer-(a)

Question- The internal energy of a gram-molecule of an ideal gas depends on

(a) pressure alone

(b) volume alone

(c) temperature alone

(d) both on pressure as well as temperature

Answer-(c)

Question- If the pressure in a closed vessel is reduced by drawing out some gas, the mean-free path of the molecules

(a) is decreased

(b) is increased

(c) remains unchanged

(d) increases or decreases according to the nature of the gas

Answer-(b)

Question- Pressure exerted by a perfect gas is equal to

(a) mean kinetic energy per unit volume

(b) half of mean kinetic energy per unti volume

(c) two third of mean kinetic energy per unit volume

(d) one third of mean kinetic energy per unit volume

Answer-(c)

Question- In a diatomic molecules, the rotational energy at a given temperature

(a) obeys Maxwell’s distribution

(b) have the same volue for all molecules

(c) equals the translational kinetic energy for each molecule.

(d) None of these

Answer-(a)

Question-  Which of the given statement(s) is/are false ?
I. All molecules in a gas do not have same velocity.
II. For a gas there is distribution of velocities of the molecules.
III. There is no preferred direction of velocity of the molecules.

(a) I and II

(b) II and III

(c) I and III

(d) I, II and III

Answer-(d)

Question- The internal energy of an ideal gas is

(a) the sum of total kinetic and potential energies.

(b) the total translational kinetic energy.

(c) the total kinetic energy of randomly moving molecules.

(d) the total kinetic energy of gas molecules.

Answer-(d)

101. If two vessels A and B contain the same gas but the volume of vessel A is twice that of B and temperature and pressure of gas A is twice that of gas in B, then the ratio of gas molecules in A and B is

(a) 1 : 2

(b) 1 : 4

(c) 4 : 1

(d) 2 : 1

Answer-(d)