Question

Carnot cycle (reversible) of a gas represented by a Pressure − Volume curve is shown in the diagram.
Consider the following statements:
Which of these are correct
$(1$ Area $ABCD$= Work done on the gas
$(2$ Area $ABCD$= Net heat absorbed
$(3$ Change in the internal energy in cycle =0

Diagram

• A. $\text{II and III}$
• B. $\text{II only}$
• C. $\text{I only}$
• D. $\text{I,II and III}$

Answer 1

The correct option is A $\text{II and III}$

Work is done by the gas (as cyclic process is clockwise)
$W=\text{Area}ABCD$

Change in internal energy of the cycle is $0$ as initial and final point is same,
$\Delta U=0$

So, from the first law of thermodynamics net heat absorbed,
$Q=\Delta W=\text{Area}ABCD$

Final answer: (C)