For a reversible process, necessary condition is -

(1) In the whole cycle of the system, the loss of any type of heat energy should be zero

(2) That the process should be too fast

(3) That the process should be slow so that the working substance should remain in thermal and mechanical equilibrium with the surroundings

(4) The loss of energy should be zero and it should be quasistatic

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

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

The temperature of reservoir of Carnot's engine operating with an efficiency of 70% is 1000K. The temperature of its sink is -

(1) 300 K

(2) 400 K

(3) 500 K

(4) 700 K

In a Carnot engine, when \(T_2=0^\circ \mathrm{C}\) and \(T_1=200^\circ \mathrm{C},\) its efficiency is \(\eta_1\) and when \(T_1=0^\circ \mathrm{C}\) and \(T_2=-200^\circ \mathrm{C},\) its efficiency is \(\eta_2.\) What is the value of \(\frac{\eta_1}{\eta_2}?\)

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%

A Carnot engine operates between 227°C and 27°C . Efficiency of the engine will be -

(1) $\frac{1}{3}$

(2) $\frac{2}{5}$

(3) $\frac{3}{4}$

(4) $\frac{3}{5}$

Efficiency of a Carnot engine is 50% when temperature of outlet is 500 K. In order to increase efficiency up to 60% keeping temperature of intake the same what is temperature of outlet ?

(1) 200 K

(2) 400 K

(3) 600 K

(4) 800 K

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) $\frac{\eta }{2}$

(2) η

(3) 2η

(4) 3η

An engine is supposed to operate between two reservoirs at temperature 727°C and 227°C. The maximum possible efficiency of such an engine is -

(1) 1/2

(2) 1/4

(3) 3/4

(4) 1