UPSC Prelims PYQ 2013: Cause of Thunder During a Thunderstorm

During a thunderstorm, the thunder in the skies is produced by

1. the meeting of cumulonimbus clouds in the sky
2. lightning that separates the nimbus clouds
3. violent upward movement of air and water particles

Select the correct answer using the codes given below.

1. 1 only
2. 2 and 3
3. 1 and 3
4. None of the above produces the thunder

Explanation

Option (d) is the correct answer

• Thunder is the sound caused by the discharge of atmospheric electrical charge (plasma ― ionised gas medium ― 30,000 °C) by lightning. The channel pressure of the electric charge greatly exceeds the ambient (surrounding) pressure, and the channel expands at a supersonic rate (speed of sound).
• The resultant shock wave decays rapidly with distance and is eventually heard as thunder once it slows to the speed of sound. Thunderbolt is a flash of lightning accompanied by a crash of thunder.
• Here’s why the options are incorrect:
• The meeting of cumulonimbus clouds in the sky: While cumulonimbus clouds are associated with thunderstorms, their meeting doesn’t directly cause thunder.
• Lightning that separates the nimbus clouds: Lightning can occur in thunderstorms, but it doesn’t separate the clouds. Lightning creates a rapid expansion of air, which causes the sound of thunder.
• Violent upward movement of air and water particles: This contributes to the formation of thunderstorms and lightning but doesn’t directly produce thunder.

Answer: (d) None of the above produces the thunder; Difficulty Level: Medium