One mole of diatomic ideal gas undergoes a cyclic process ABC as shown in figure. The process BC is adiabatic. The temperature at A, B and C are 400K, 800K and 600 K respectively. Choose the correct statememt.

Options

A. The change in internal energy in the process AB is
B. The change in internal energy in the process BC is
C. The change in internal energy in whole cyclic process is 250 R
D. The change in internal energy in the process CA is 700 R

Answer

B

Explanation

`triangleU_(AB)=nC_(v)(T_B-T_A)=1xx(5R)/(2)(800-400)=1000R`
`triangleU_(BC)=nC_(v)(T_C-T_B)=1xx(5R)/(2)(600-800)=-500R`
`triangleU_(" total ")=0`
`triangleU_(CA)=nC_(v)(T_A-T_C)=1xx(5R)/(2)(400-600)=-500R`.