The correct option is D 94R
Given,
Heat added to the gas Q=+15 J
Work done by the gas W=+5 J
According to first law of thermodynamics
Q=ΔU+W
⇒15=ΔU+5
⇒ΔU=+10 J
But we know that, ΔU=nCVΔT
⇒nCVΔT=+10 J ....(1)
Also, heat absorbed in the process Q=nCΔT
where C is the molar heat capacity for the gas during the process.
Thus, nCΔT=+15 J .....(2)
From (1) & (2) we get,
CCV=32⇒C=3CV2
For a monoatomic gas, we know that CV=3R2
⇒C=32×3R2
⇒C=94R
Thus, option (d) is the correct answer.