BITSAT 2018 Slot 2 Solved Paper

Helium is monoatomic gas, for which
CV=

3

2

R,Cp=

5

2

R
Work done by the gas in one complete cycle W= area ABCDA=p0V0
From A to B
Heat given to gas =nCVΔT
=1×(

3

2

R)×ΔT=

3

2

V0(Δp) =

3

2

V0p0
From B to C, heat given to gas =nCpΔT
=1×(

5

2

R)×ΔT=

5

2

(2p0)ΔV =5p0V0
Efficiency of cycle =

Work done by the gas ∕cycle

Total heat given to gas ∕cycle

=

p0V0

32p0V0+5p0V0

=

2

13

Efficiency (%)=

2

13

×100=15.4%