Consider a cycle followed by an engine, (figure)
1 to 2 is isothermal 2 to 3 is adiabatic 3 to 1 is adiabatic
such a process does not exist because

Options

A. heat is completely converted to mechanical energy in such a process which is not possible
B. mechanical energy is completely converted to heat in this process, which is not possible
C. curves representing two adiabatic processes can intersect
D. curves representing an adiabatic process and an isothermal process don't intersect

Answer

A

Explanation

In one complete cycle, `1rarr2rarr3rarr3rarr1`, the systeme returns to its initial state so dU = 0 and dQ =dW i.e het is completyely cnverted in to mechanical energy in the given prpocess .It is not possible further two adiabatic curve `2rarr3and 3rarr1` connot intesect each other.