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Question:

5.6 L of helium gas at STP is adiabatically compressed to 0.7 L. Taking the initial temperature to be T1, the work done in the process is ?

15/8 RT1

9/2 RT1

3/2 RT1

9/8 RT1

Solution:

TVγ-1 = C
T1(5.6)2/3 = T2(0.7)2/3 (gamma for monoatomic gas is 5/3)
So, T2 = 4T1
Work done on system = nRΔT/(γ-1) = 9/8 RT1