Helium gas goes through a cycle ABCDA (consisting of two isochoric and two isobaric lines) as shown in figure. Efficiency of this cycle is nearly :

Options

A. `12.5%`
B. `15.4%`
C. `9.1%`
D. `10.5%`

Answer

B

Explanation

`W` = Area bounded by curve = `P_(0)V_(0)`
`Q_(AB) = nC_(V)DeltaT = n xx (3)/(2)R xx DeltaT = (3)/(2)P_(0)V_(0)`
`Q_(BC) = nC_(P)DeltaT = n xx (5)/(2)R xx DeltaT = 5P_(0)V_(0)`
Total heat supplied = `(3)/(2)P_(0)V_(0) + 5P_(0)V_(0) = (13)/(2)P_(0)V_(0)`
`eta = (W)/(Q) xx 100 = (P_(0)V_(0))/(13P_(0)V_(0)) xx 100 = 15.4%`