`P - V` diagram of a cyclic process `ABCA` is as shown in Fig. Choose the correct alternative

Options

A. `Delta Q_(A) rarr._(B)` is negative
B. `Delta U_(b) rarr._(c)` is negative
C. `Delta U_(c) rarr._(A)` is negative
D. `Delta W_(CAB)` is negative

Answer

A, B, D

Explanation

During process `A` and `B`, pressure and volume both are decreasing. Therefore , temperature and hence internal energy of the gas will decrease `(T prop PV)` or `Delta V_(A) rarr _(B)=` negative. Further, `Delta W_(A) rarr _(B)` is negative.
In processs `B` to `C`, pressure of the gas is constant while volume is increasing . Hence, temperature should increase or `DeltaU_(B) rarr _(C) =` postive. During `C` to `A` volume is constant while pressure is increasing.
Therefore, temperature and hence internal energy of the gas should increase or `Delta U _(C) rarr _(A)=` positive. During process `CAB`, volume of the gas is decreasing. Hence, work done by the gas is negative.