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

One mole of an ideal gas from an initial state A undergoes via two processes. It first undergoes isothermal expansion from volume V to 3V and then its volume is reduced from 3V to V at constant pressure. The correct P-V diagram representing the two processes is -

An ideal gas goes from state \(A\) to state \(B\) via three different processes, as indicated in the \(P\text-V\) diagram. If \(Q_1,Q_2,Q_3\)${\mathrm{}}_{}$ indicates the heat absorbed by the gas along the three processes and \(\Delta U_1, \Delta U_2, \Delta U_3\) indicates the change in internal energy along the three processes respectively, then:

A mass of diatomic gas ($\gamma$=1.4) at a pressure of 2 atm is compressed adiabatically so that its temperature rise from $27°\mathrm{C}$ to $927°\mathrm{C}.$ The pressure of the gas is final state is-

(1) 28 atm                                           

(2) 68.7 atm

(3) 256 atm                                           

(4) 8 atm

If $∆U and ∆W$ represent the increase in internal energy and work done by the system respectively in a thermodynamical process,which of the following is true?

(1) $∆U=-∆W,$ in a adiabatic process

(2) $∆U=∆W,$ in a isothermal process

(3) $∆U=∆W,$ in adiabatic process

(4) $∆U=-∆W,$in a isothermal process 

A monoatomic gas at pressure ${\mathrm{p}}_1$ and ${\mathrm{V}}_1$ is compressed adiabatically to $\frac{1}{8}\mathrm{th}$ its original volume. What is the final pressure of the gas ?

(1) $64 {\mathrm{p}}_1$                                   

(2) ${\mathrm{p}}_1$

(3) $16 {\mathrm{p}}_1$                                   

(4) $32 {\mathrm{p}}_1$