The moles of an ideal monoatomic gas perform a cycle shown in figure. The gas temperatures in different states are `T_(1) = 400 K, T_(2) = 800 K, T_(3) = 2400 K`, and `T_(4) = 1200 K`. The work done by the gas during the cycle is :

Options

A. `5 kJ`
B. `10 kJ`
C. `15 kJ`
D. `20 kJ`

Answer

D

Explanation

d. Process `_(1 rarr 2)` and Process `_(3 rarr 4)`
are isochroic process.
`W_(12) = 0`
`W_(24) = 0`
`W_(23) = n R (T_(3) - T_(2))`
`= 3 R (2400 - 800) = 4800 R`
`W_(41) = n R (T_(1) - T_(4))`
`= 3 R (400 - 1200) = - 2400 R`
`W = (4800 - 1200) R = 2400 R = 20 KJ`