JEE Physics Kinetic Theory MCQS Set B

Question. A container contains 32 g of O₂ at a temperature T. The pressure of the gas is P. An identical container containing 4 g of H2 at a temperature 2T has a pressure of
(a) 4P
(b) P
(c) P₁₈
(d) 8P

Answer: A

Question. 50 cal of heat is required to raise the temperature of 1 mole of an ideal gas from 20°C to 25°C, while the pressure of the gas is kept constant. The amount of heat required to raise the temperature of the same gas through same temperature range at constant volume is (R = 2 cal/mol/K)
(a) 40 cal
(b) 50 cal
(c) 60 cal
(d) 70 cal

Answer: A

Question. An ideal gas undergoes a polytropic given by equation PVⁿ = constant. If molar heat capacity of gas during this process is arithmetic mean of its molar heat capacity at constant pressure and constant volume then value of n is
(a) –1
(b) +1
(c) Zero
(d) None of these

Answer: A

Question. If different ideal gases are at the same temperature, pressure and have same volume, then all gases have same
(a) Number of molecules
(b) Internal energy per mole
(c) Density
(d) Most probable speed

Answer: A

Question. The internal energy of 10 g of nitrogen at N.T.P. is about
(a) 2025 J
(b) 2575 J
(c) 3721 J
(d) 4051 J

Answer: A

Question. According to C.E. van der Waal, the interatomic potential varies with the average interatomic distance (R) as
(a) R^–6
(b) R^–4
(c) R^–3
(d) R^–2

Answer: A

Question. Two container A and B are partly filled with water and closed. The volume of A is twice that of B and it contains half the amount of water in B. If both are at same temperature, the water vapour in the container will have pressure in the ratio of
(a) 1 : 1
(b) 2 : 1
(c) 4 : 1
(d) 1 : 2

Answer: A

Question. At constant volume, temperature is increased then
(a) Number of collisions per unit time will increase
(b) Collision on walls will be less
(c) Collisions will be in straight lines
(d) Collisions will not change

Answer: A

Question. According to kinetic theory of gases, at absolute zero temperature
(a) Molecular motion stops
(b) Water freezes
(c) Liquid helium freezes
(d) Liquid hydrogen freezes

Answer: A

Question. One mole of an ideal monoatomic gas requires 207 J heat to raise the temperature by 10 K when heated at constant pressure. If the same gas is heated at constant volume to raise the temperature by the same 10 K, the heat required is [Given the gas constant R = 8.3 J/mol-K]
(a) 124 J  
(b) 215.3 J
(c) 29 J
(d) 198.7 J

Answer: A

Question. The temperature of gas is raised from 27°C to 927°C. The rms speed is
(a) Get doubled
(b) Remain the same
(c) Gets halved
(d) None of these

Answer: A

Question. At 0 K, which of the following properties of a gas will be zero?
(a) Kinetic energy
(b) Potential energy
(c) Density
(d) Mass

Answer: A

Question. The degrees of freedom of a triatomic gas is (consider moderate temperature)
(a) 6
(b) 4
(c) 2
(d) 8

Answer: A