For which combination of working temperatures, the efficiency of 'Carnot's engine' is the least?

Options

A. 60 K, 40 K
B. 40 K, 20 K
C. 80 K, 60 K
D. 100 K, 80 K

Answer

D

Explanation

We know that,
`eta = (1-(T_(L))/(T_(H)))xx100`
According to trial and error method
`eta=(1-(80)/(100))xx100`
`eta = ((100-80)/(100))xx100`
`eta = (20)/(100)xx100=20%`