The efficiency of Carnot's engine operating between reservoirs, maintained at temperatures 27°C and –123°C, is
(1) 50%
(2) 24%
(3) 0.75%
(4) 0.4%
An ideal heat engine working between temperature T1 and T2 has an efficiency η, the new efficiency if both the source and sink temperature are doubled, will be
(1)
(2) η
(3) 2η
(4) 3η
The temperature of sink of Carnot engine is 27°C. Efficiency of engine is 25%. Then temperature of source is -
(1) 227°C
(2) 327°C
(3) 127°C
(4) 27°C
A Carnot's engine used first an ideal monoatomic gas then an ideal diatomic gas. If the source and sink temperature are 411°C and 69°C respectively and the engine extracts 1000 J of heat in each cycle, then area enclosed by the PV diagram is -
(1) 100 J
(2) 300 J
(3) 500 J
(4) 700 J
A gas expands under constant pressure P from volume V1 toV2. The work done by the gas is
(1)
(2)
(3)
(4)
The adiabatic Bulk modulus of a perfect gas at pressure P is given by
(1) P
(2) 2P
(3) P/2
(4) γ P
If denotes the ratio of two specific heats of a gas, the ratio of slopes of adiabatic and isothermal PV curves at their point of intersection is
(1)
(2)
(3)
(4)
During the adiabatic expansion of 2 moles of a gas, the internal energy of the gas is found to decrease by 2 joules, the work done during the process by the gas will be equal to -
(1) 1 J
(2) –1 J
(3) 2 J
(4) – 2 J
The latent heat of vaporisation of water is 2240 J/gm. If the work done in the process of expansion of 1 g is 168 J, then increase in internal energy is
(1) 2408 J
(2) 2240 J
(3) 2072 J
(4) 1904 J
A vessel containing 5 litres of a gas at 0.8 m pressure is connected to an evacuated vessel of volume 3 litres. The resultant pressure inside will be (assuming whole system to be isolated)
(1) 4/3 m
(2) 0.5 m
(3) 2.0 m
(4) 3/4 m