The temperature inside a refrigerator is ${t_2}^{\circ }C$and the room temperature is ${t_1}^{\circ }C$. The amount of heat delivered to the room for each joule of electrical energy consumed ideally will be:

1. $\frac{t_1}{t_1-t_2}$

2.  $\frac{t_1+273}{t_1-t_2}$

3. $\frac{t_2+273}{t_1+t_2}$

4.  $\frac{t_1+t_2}{t_1+273}$

A gas is compressed isothermally to half its initial volume. The same gas is compressed separately through an adiabatic process until its volume is again reduced to half. Then:

Figure below shows two paths that may be taken by a gas to go from a state A to a state C. In process AB, 400 J of heat is added to the system and in process BC, 100 J of heat is added to the system. The heat absorbed by the system in the process AC will be-

(a) 380 J 
(b) 500 J
(c) 460 J
(d) 300 J

One mole of an ideal diatomic gas undergoes a transition from A to B along a path AB as shown in the figure.

The change in internal energy of the gas during the transition is

(1) 20 kJ

(2) -20 kJ

(3) 20 J

(4) -12 kJ

An ideal gas is compressed to half its initial volume by means of several processes. Which of the following processes results in the maximum work being done on the gas?
1. Adiabatic
2. Isobaric
3. Isochoric
4. Isothermal

The coefficient of performance of a refrigerator is 5. If the temperature inside freezer is -20°C, the temperature of the surroundings to which it rejects heat is  -

1. 31°C

2. 41°C

3. 11°C

4. 21°C

A thermodynamic system undergoes cyclic process ABCDA as shown in figure. The work done by the system in the cycle is

(1) ρ_oV_o 

(2) 2ρ_oV_o

(3) ρ_oV_o/2

(4)zero

A gas is taken through the cycle A→B→C→A, as shown. What is the net work done by the gas?

(1)2000J

(2)1000J

(3)Zero

(4)-2000J

During an adiabatic process, the pressure of a gas is found to be proportional to the cube of its temperature. The ratio of C_P/C_V for the gas is equal to:

A thermodynamic system is taken through the cycle ABCD as shown in figure. Heat rejected by the gas during the cycle is 

(a)2 pV                                     (b)4 pV

(c)$\frac{1}{2}pV$                                    (d)pV