An ideal gas initially at P1, V1 is expanded to P2, V2 and then compressed adiabatically to the same volume V1 and pressure P3. If W is the net work done by the gas in complete process, which of the following is true ?
W > 0 ; P3 > P1
W < 0 ; P3 > P1
W > 0 ; P3 < P1
The equation of state for 5g of oxygen at a pressure p and temperature T, when occupying a volume V, will be
pV = (5/32)RT
pV = 5 RT
pV = (5/2)RT
pV = (5/16)RT
In a adiabatic process, the state of a gas is changed from P1, V1, T1 to P2, V2, T2. Which of the following relations is correct ?
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, the final temperature of gas will be:
(T + 2.4)K
(T - 2.4)K
(T + 4)K
(T - 4)K
The efficiency of a Carnot engine operating between temperatures of 100oC and -23oC will be
Which statement is incorrect ?
All reversible cycles have same efficiency.
Reversible cycle has more efficiency than an irreversible one.
Carnot cycle is a reversible one.
Carnot cycle has the maximum efficiency of all the cycles.
An engine has an efficiency of 1/6. When the temperature of sink is reduced by 62oC, its efficiency is doubled. Temperature of the source is
124oC
37oC
62oC
99oC
Which of the following is incorrect regarding the first law of thermodynamics ?
It introduces the concept of the internal energy
It introduces the concept of the entropy
It is not applicable to any cyclic process
It is restatement of the principle of conservation of energy
A Carnot engine operating between temperatures T1 and T2 has efficiency 1/6. When T2 is lowered by 62 K, its efficiency increases to 1/3. Then T1 and T2 are, respectivley:
372 K and 310 K
372 K and 330 K
330 K and 268 K
310 K and 248 K
Which one is correct ?
In an isobaric process, ΔP = 0
In an isochoric process, ΔW = 0
In an isothermal process, ΔT = 0
In an isothermal process, ΔQ = 0