CBSE
Multiple Choice QuestionsConsider two containers P and Q containing identical gases at same temperature, pressure and volume. The gas in container P is compressed to half of its original volume isothermally while the gas in container Q is compressed to half of its original value adibatically. The ratio of final pressure of gas is
The pressure and density of a diatomic gas change adiabatically from (P1 , ρ1) to (P2 , ρ2) . If , then should be
16
32
64
128
Work of 146 kJ is performed in order to compress one kilo mole of a gas adiabatically and in this process the temperature ofthe gas increases by 7° C. The gas is (R = 8.3 J mol-1 K-1 )
diatomic
triatomic
a mixture of monoatomic and diatomic
monoatomic
One mole of an ideal gas at an initial temperature of T K does 6R joules of work adiabatically. If the ratio of specific heats of this gas at constant pressure and at constant volume is 5/3, then final temperature of the gas will be
(T − 4) K
(T + 4) K
(T − 2.4)K
(T + 2.4) K
Ten moles of an ideal gas at constant temperature 500 K is compressed from 50 L to 5 L. Work done in the process is (Given, R = 8.31 J-mol-1 - K-1 )
- 1.2 x 104 J
- 2.4 x 104 J
- 4.8 x 104 J
- 9.6 x 104 J
According to first law of thermodynamics
energy is conserved
mass is conserved
heat is constant in isothermal process
heat neither enters nor leaves system
A refrigerator is driven by 1000 W electric motor having an efficiency of 60%. The refrigerator is considered as a reversible heat engine operating between 273 K and 303 K. Time required by it to freeze 32.5 kg of water at 0°C is. (Given, latent heat of fusion of ice = 336 × 103 J-kg-1 and heat lost may be neglected).
53 min 20 s
33 min 20 s
48 min 40 s
28 min 32 s
Two spherical soap bubbles of radii r1 and r2 in vacuum combine under isothermal conditions. The resulting bubble has a radius equal to
An ideal heat engine exhausting heat at 27° C is to have 25% efficiency. It must take heat at
127 °C
227° C
327° C
None of these
Consider an ideal gas confined in an isolated closed chamber. As the gas undergoes an adiabatic expansion, the average time of collision between molecules increases to Vq , where V is the volume of the gas. The value of q is
