Answer:
Option C
Explanation:
For adiabatic process relation of temperature and volume is,
T2Vγ−12=T1Vγ−11
T2(2V)23=300(V)23
[ γ=53 for monoatomic gases ]
T2=300223≈189K
Also, in adiabatic process,
△Q=0,△U=−△W
OR △U=−nR(△T)γ−1
=−2×32×253(300−189)
≈−2.7KJ
T2≈189K,△U≈2.7KJ