AP EAMCET Engineering 26 Apr 2017 Shift 1 Paper

The total work done is equal to the area under the cyclicprocess.
W=(3P−P)(2V−V)
W=2PV
The total heat supped to the system,
Q=QAB+QBC
=ncvΔT+ncpΔT
=

3

2

RΔT+

5

2

RΔT
=

3

2

VΔP+

5

2

3PΔV
=

3

2

V(3P−2P)+

5

2

3P(2V−V)
=3PV+

15

2

PV
=

21

2

PV
The efficiency is calculated as,
η=

W

Q

×100
=

2PV

21 2 PV

×100
=19.04%
Thus, no option is correct.