A unit mass of a liquid with volume V1 is completely changed into a gas of volume V2 at a constant external pressure P and temperature T. If the latent heat of evaporation for the given mass is L, then the increase in the internal energy of the system is:
1. Zero
2.
3.
4. L
If 300 ml of a gas at 27°C is cooled to 7°C at constant pressure, then its final volume will be -
(1) 540 ml
(2) 350 ml
(3) 280 ml
(4) 135 ml
If the door of a refrigerator is kept open, then which of the following is true ?
1. Room is cooled
2. Room is heated
3. Room is either cooled or heated
4. Room is neither cooled nor heated
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 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
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 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
An ideal gas heat engine operates in Carnot cycle between 227°C and 127°C. It absorbs 6 × 104 cal of heat at higher temperature. Amount of heat converted to work is -
(1) 2.4 × 104 cal
(2) 6 × 104 cal
(3) 1.2 × 104 cal
(4) 4.8 × 104 cal
A monoatomic ideal gas, initially at temperature \(T_1\), is enclosed in a cylinder fitted with a frictionless piston. The gas is allowed to expand adiabatically to a temperature \(T_2\) by releasing the piston suddenly. If \(L_1\) and \(L_2\) are the lengths of the gas column before and after expansion, respectively, then \(\frac{T_1}{T_2}\) is given by:
1. \(\left(\frac{L_1}{L_2}\right)^{\frac{2}{3}}\)
2. \(\frac{L_1}{L_2}\)
3. \(\frac{L_2}{L_1}\)
4. \(\left(\frac{L_2}{L_1}\right)^{\frac{2}{3}}\)