Thermal efficiency of a Carnot engine can approach 100%, only when the temperature of the

A. Cold reservoir approaches zero

B. Hot reservoir approaches infinity

C. Either A or B

D. Neither A nor B

Answer: Option C

Solution(By Examveda Team)

Since Efficiency of a Carnot engine is $$\aleph = 1 - \frac{{{T_2}}}{{{T_1}}}$$
So, when the cold reservoir temperature is zero or when the hot reservoir temperature is infinity we can say that the efficiency is $$100\% .$$
But this is purely an impossible situation even under ideal conditions as given by second law of thermodynamics.