Question

A Carnot engine takes `3xx10^6cal`. of heat from a reservoir at `62^@C`, and gives it to a sink at `27^@C`. The work done by the engine is
A. `4.2xx10^(6)J`
B. `8.4xx10^(6)J`
C. `16.8xx10^(6)J`
D. zero

Answer 1

Correct Answer - B
`eta=1-(T_2)/(T_1)=W/Q implies W =(1-(T_1)/(T_2))Q={1-((273+27))/((273+627))}`
`implies W = (1-300/900)xx3xx10^(6)`
`=2xx10^(6)xx4.2J = 8.4xx10^(6)J`.