Thermodynamics ...

In the isothermal expansion of a gas :

The efficiency of a heat engine : 

Which of the following is true in the case of an adiabatic process where $$\gamma =C_{p}/C_{v}$$?

A sink, that is the system where heat is rejected, is essential for the conversion of heat into work. From which law does the above inference follow?

Which of the following laws of thermodynamics leads to the inference that it is difficult to convert whole of heat into work :

When heat is added to a system, which of the following is not possible? 

For an adiabatic process the relation between V and T is given by 

The second law of thermodynamics implies : 

$$dU + dW = 0$$ is valid for :

The ratio of slopes of adiabatic and isothermal curves is :