Answer:
η = 0.5 = 50%
Explanation:
The efficiency of a Carnot engine is given by the following formula:
η = (T₁ - T₂)/T₁
η = 1 - T₂/T₁
where,
η = Efficiency of the engine
T₁ = Absolute Temperature of Hot Reservoir
T₂ = Absolute Temperature of Cold Reservoir
but, according to given question the absolute temperature of hot reservoir is twice that of the cold reservoir. Therefore,
T₁ = 2 T₂
Substituting this in equation, we get:
η = 1 - T₂/2T₂
η = 1 - 1/2
η = 0.5 = 50%