Correct Answer - D
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`