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

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

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

If $\gamma$ 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) $\frac{1}{\gamma }$

(2) $\gamma$

(3) $\gamma -1$

(4) $\gamma +1$

The adiabatic Bulk modulus of a perfect gas at pressure P is given by 

(1) P

(2) 2P

(3) P/2

(4) γ P

A gas expands under constant pressure P from volume V₁ toV₂. The work done by the gas is 

(1) $P(V_2-V_1)$

(2) $P(V_1-V_2)$

(3) $P(V_1^{\gamma }-V_2^{\gamma })$

(4) $P\frac{V_1{V}_2}{V_2-V_1}$

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

(2) η

(3) 2η

(4) 3η