Twp cylinders of equal size are filled with equal amount of ideal

twp-cylinders-of-equal-size-are-filled-with-equal-amount-of-ideal

Twp cylinders of equal size are filled with equal amount of ideal diatomic gas at room temperature. Both the cylinders are fitted with pistons. In cylinder A the piston is free to move, while in cylinder B the piston is fixed. When same amount of heat is added to cylinder A raises by 20 K. What will be the rise temperature of gas in cylinder B?

A. 28K

B. 20K

C. 15K

D. 10K

I had been asked this question during an interview.

My question is based upon Isothermic and Adiabatic Process in portion Kinetic Theory of Gases of Engineering Physics I

The correct answer is A. 28K

To elaborate: For gas in cylinder A, Q = nCp ∆T1

For gas in cylinder B, Q = nCv ∆T2

∆T2=Cp/Cv  ∆T1=7/5×20=28K.