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:

1.	compressing the gas through an adiabatic process will require more work to be done.
2.	compressing the gas isothermally or adiabatically will require the same amount of work to be done.
3.	which of the case (whether compression through isothermal or through the adiabatic process) requires more work to be done will depend upon the atomicity of the gas.
4.	compressing the gas isothermally will require more work to be done.

 

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

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

An ideal gas goes from state A to state B via three different processes, as indicated in the P-V diagram. If ${\mathrm{Q}}_1,$ ${\mathrm{Q}}_2,$ ${\mathrm{Q}}_3$ indicates the heat absorbed by the gas along the three processes and $∆{\mathrm{U}}_1,$ $∆{\mathrm{U}}_2,$ $∆{\mathrm{U}}_3$ indicates the change in internal energy along the three processes respectively, then:

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) $32 {\mathrm{p}}_1$

The internal energy change in a system that has absorbed 2 kcal of heat and done 500 J of work is 

(1) 8900 J                                     

(2) 6400 J

(3) 5400 J                                     

(4) 7900 J

If Q, E and W denote respectively the heat added, change in internal energy and the work done in a closed cyclic process, then

(1) W=0                                 

(2) Q=W=0

(3) E=0                                   

(4) Q=0

In a thermodynamic process, pressure of a fixed mass of a gas is changed in such a manner that the gas molecules absorb 30 J of heat and 10 J of work is done by the gas. If the initial internal energy of the gas was 40 J, then the final internal energy will be -

(1) 30 J

(2) 20 J

(3) 60 J

(4) 40 J