Two Carnot engines A and B are operated in series. The engine A receives heat from the source at temperature T₁ and rejects the heat to the sink at temperature T. The second engine B receives the heat at temperature T and rejects to its sink at temperature T₂. For what values of T the efficiencies of the two engines are equal

A system is taken from state a to state c by two paths adc and abc as shown in the figure. The internal energy at a is $${U_a} = 10\,J$$. Along the path adc the amount of heat absorbed dQ₁ $$=$$ 50 J and the work obtained dW₁ $$=$$ 20 J whereas along the path abc the heat absorbed dQ₂ = 36 J. The amount of work allong the path abc is

Which of the following relations does not give the equation of an adiabatic process, where terms have their usual meaning?

During an adiabatic process, the pressure of a gas is found to be proportional to the cube of its temperature. The ratio of $${{{C_p}} \over {{C_p}}}$$ for the gas is