Question

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

Answer 1

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.