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 gas is taken through the cycle
A $$ \to $$ B $$ \to $$ C $$ \to $$ A, as shown. what is the net work done by the gas?

In the given (V $$-$$ T) diagram, what is the relation between pressure P₁ and P₂?

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