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

Options

A. The change in internal energy in the process AB is - 350 R.
B. The change in internal energy in the process BC is - 500 R.
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

`DeltaU=nC_V DeltaT` for diatomics gas `C_V=5/2 R`
`therefore DeltaU=(1)5/2 R(T_2-T_1)`
`=(1)(5/2R)(600-800)`
`=-(5R)/2xx200`
=-500 R