Clear sky nights are cooler than cloudy sky nights due to

Correct answer: (b) radiation

Explanation

On cloudy nights, the amount of water vapour in the atmosphere is higher than on clear nights. Water vapour absorbs the outgoing terrestrial radiation; therefore, cloudy nights feel comparatively warmer. In addition, on clear nights, due to lower water vapour in the atmosphere, terrestrial radiation easily escapes into space at night, and clear nights feel colder. In fact, the atmosphere behaves like a greenhouse.