P-V diagram of a cyclic process ABCA is as shown in figure. Choose the correct statement
(1) = negative
(2) = positive
(3) = negative
(4) All of these
(4) During process A to B, pressure and volume both are decreasing. Therefore, temperature and hence, internal energy of the gas will decrease (T ∝ PV) or negative. Further is also negative as the volume of the gas is decreasing. Thus is negative.
In process B to C pressure of the gas is constant while volume is increasing. Hence temperature should increase or = positive. During C to A volume is constant while pressure is increasing. Therefore, temperature and hence, internal energy of the gas should increase or = positive. During process CAB volume of the gas is decreasing. Hence, work done by the gas is negative.