Why are dewdrops not formed on a cloudy night?
- AClouds absorb the radiation released from the Earth's surface.
- BClouds reflect back the Earth's radiation.Correct
- CThe Earth's surface would have low temperature on cloudy nights.
- DClouds deflect the blowing wind to ground level.
Explanation
Dewdrops are not formed on cloudy nights because clouds act as a blanket, reflecting back the Earth's longwave radiation (heat) towards the surface. This prevents the ground from cooling sufficiently to reach the dew point temperature. Without adequate cooling, water vapour in the air near the ground does not condense into dew.
On clear nights, the Earth's surface radiates heat freely into space, cooling rapidly and allowing dew to form.
Related questions
More UPSC Prelims practice from the same subject and topic.
- Prelims 2019GS1geography
On 21st June, the Sun
- Prelims 2019GS1geography
In the context of which of the following do some scientists suggest the use of cirrus cloud thinning technique and the injection of sulphate aerosol into stratosphere?
- Prelims 2019GS1geography
Which one of the following National Parks lies completely in the temperate alpine zone?
- Prelims 2019GS1geography
Which one of the following groups of plants was domesticated in the 'New World' and introduced into the 'Old World'?
- Prelims 2019GS1geography
Consider the following statements: 1. Asiatic lion is naturally found in India only. 2. Double-humped camel is naturally found in India only. 3. One-horned rhinoceros is naturally found in India only.…
- Prelims 2019GS1geography
Consider the following pairs: Famous place River 1. Pandharpur : Chandrabhaga 2. Tiruchirappalli : Cauvery 3. Hampi : Malaprabha Which of the pairs given above are correctly matched?