CBSE Class 11 Physics Kinetic Energy Worksheet Set A

Question. Boyle's law is applicable for an 
(a) adiabatic process
(b) isothermal process
(c) isobaric process
(d) isochoric process

Answer: B

Question. A cylinder containing an ideal gas is in vertical position and has a piston of mass M that is able to move up or down without friction (figure). If the temperature is increased
(a) both p and V of the gas will change
(b) only p will increase according to Charles' law
(c) V will change but not p
(d) p will change but not V

Answer: C

Question. Volume versus temperature graphs for a given mass of an ideal gas are shown in figure. At two different values of constant pressure. What can be inferred about relation between p₁ and p₂?
(a) p₁ > p₂
(b) p₁ = p₂
(c) p₁ < p₂
(d) Data is insufficient

Answer: A

Question. A vessel has 6g of hydrogen at pressure P and temperature 500K. A small hole is made in it so that hydrogen leaks out. How much hydrogen leaks out if the final pressure is P/2 and temperature falls to 300 K ?
(a) 2g
(b) 3g
(c) 4g
(d) 1g

Answer: D

Question. The molecules of a given mass of a gas have r.m.s. velocity of 200 ms^–1 at 27°C and 1.0 × 10⁵ Nm^–2 pressure. When the temperature and pressure of the gas are respectively, 127°C and 0.05 × 105 Nm^–2, the r.m.s. velocity of its molecules in ms^–1 is :
(a) 100√2
(b) 400/√3
(c) 100 √2/3
(d) 100/3

Answer: B

Question. At identical temperatures, the rms speed of hydrogen molecules is 4 times that for oxygen molecules. In a mixture of these in mass ratio H₂ : O₂ = 1:8, the rms speed of all molecules is n times the rms speed for O₂ molecules, where n is
(a) 3
(b) 4/3
(c) (8/3)^1/2
(d) (11)1/2

Answer: D

Question. Two monatomic ideal gases 1 and 2 of molecular masses m₁ and m₂ respectively are enclosed in separate containers kept at the same temperature. The ratio of the speed of sound in gas 1 to that in gas 2 is given by
(a) √m₁/m₂
(b) √m₂/m₁
(c) m₁/m₂
(d) m₂/m₁

Answer: A

Question. A vessel of volume V contains a mixture of 1 mole of hydrogen and 1 mole oxygen (both considered as ideal).
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

Answer: B

Question. The amount of heat energy required to raise the temperature of 1g of Helium at NTP, from T₁K to T₂K is
(a) 3/2 NakB(T₂ – T₁)
(b) 3/4 NakB(T₂ – T₁)
(c) 3/4 NakB T₂/T₁
(d) 3/8 NakB(T₂ – T1)

Answer: D

Question. In a vessel, the gas is at a pressure P. If the mass of all the molecules is halved and their speed is doubled, then the resultant pressure will be 
(a) 4P
(b) 2P
(c) P
(d) P/2

Answer: B

Question. The mean free path of molecules of a gas, (radius ‘r’) is inversely proportional to : 
(a) r³
(b) r²
(c) r
(d) √r

Answer: B

Question. If pressure of a gas contained in a closed vessel is increased by 0.4% when heated by 1ºC, the initial temperature must be
(a) 250 K
(b) 250ºC
(c) 2500 K
(d) 25ºC

Answer: A

Question. In Vander Waal’s equation the critical pressure P_c is given by
(a) 3 b
(b) a/27 b²
(c) 27a/b²
(d) b²/a

Answer: B

Question. The ratio of the specific heats C_p/C_v = γ in terms of degrees of freedom (n) is given by
(a) (1+n/3)
(b) (1+2/n)
(c) (1+n/2)
(d) (1+1/n)

Answer: B

Question. One mole of an ideal diatomic gas undergoes a transition from A to B along a path AB as shown in the figure. 
The change in internal energy of the gas during the transition is: 
(a) – 20 kJ
(b) 20 J
(c) –12 kJ
(d) 20 kJ

Answer: A

Question. Which one the following graphs represents the behaviour of an ideal gas ? 

Answer: B

Question. 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 (considering all gases to be ideal)
(a) same as the pressure initially
(b) 2 times the pressure initially
(c) 10 times the pressure initially
(d) 20 times the pressure initially

Answer: D

DIRECTIONS for Each of these question contains two statements: STATEMENT-1 (Assertion) and STATEMENT-2 (Reason). Answer these questions from the following four options.
(a) Statement-1 is True, Statement-2 is True; Statement-2 is a correct explanation for Statement -1
(b) Statement-1 is True, Statement -2 is True; Statement-2 is NOT a correct explanation for Statement - 1
(c) Statement-1 is True, Statement- 2 is False
(d) Statement-1 is False, Statement -2 is True

Question. Statement 1 : The total translational kinetic energy of all the molecules of a given mass of an ideal gas is 1.5 times the product of its pressure and its volume.
Statement 2 : The molecules of a gas collide with each other and the velocities of the molecules change due to the collision.

Answer: B

Question. Statement 1 : Mean free path of a gas molecules varies inversely as density of the gas.
Statement 2 : Mean free path varies inversely as pressure of the gas.

Answer: A

Question. Statement 1 : The ratio Cv/Cp for a monatomic gas is less than for a diatomic gas.
Statement 2 : The molecules of a monatomic gas have more degrees of freedom than those of a diatomic gas.

Answer: C

Question. Statement 1 : Air pressure in a car tyre increases during driving.
Statement 2 : Absolute zero temperature is not zero energy temperature.

Answer: B