A Carnot enginer abosrbs an amount Q of heat from a reservoir at an absolute temperature T and rejects heat to a sink at a temperature of `T//3`. The amount of heat rejects is

Options

A. `Q/4`
B. `Q/3`
C. `Q/2`
D. `(2Q)/3`

Answer

B

Explanation

We know that efficiency of carnot engine
`eta = I -T_(L)/T_(H)`
Also, Efficiency of Heat engine `=("Work output")/("Heat input")`
`therefore I - T_(L)/T_(H) =W/Q_(s) rArr W = Q_(s) (1-T_(L)/T_(H))`
`rArr W =Q(1-(T//3))/T = 2/3 Q`
Hence heat rejected `=Q -2/3 Q = Q/3`