In a cyclic process, the change in internal energy (∆U) is zero. According to the first law of thermodynamics: ∆U=∆q+∆W Since ∆U=0, it follows that: ∆q=−∆W From the graph, the work done ( ∆W ) is equal to the area under the curve. In this case, the process involves a circular path, so the work done can be calculated as the area of the circle: Area of circle =πr2 Given that the radius (r) of the circle is half the difference between the maximum and minimum values on the graph, r=‌
25−5
2
=10 Thus, the area is: π×(10)2=π×100 Therefore, the heat absorbed (∆q) is: ∆q=100πJ