Question

Which one of the following(s) is/are correct for a cyclic process as shown in figure?

• A. $dU=0$
• B. $q=-w$
• C. $314$ J
• D. $31.4$ J

Answer 1

Answer: (A), (B), (C)

$dU=0$
$q=-w$
$314$ J

The First Law of Thermodynamics states that energy can be converted from one form to another with the interaction of heat, work and internal energy, but it cannot be created nor destroyed, under any circumstances. Mathematically, this is represented as

$\Delta H=\Delta U+W$

with,

$\Delta H$ is the heat exchanged between a system and its surroundings,

$\Delta U$ is the total change in internal energy of a system,

$\Delta nRT$ is the work done by or on the system.

For a cyclic process, change in internal energy is zero. So, heat absorbed during the process is equal to the work done during the process which is equal to the area under the graph. Area under the graph is equal to the area of the circle.

$Radius=10Area=\pi r^2=\frac{22}{7}\times {10}^{2}J=314J$