Question

1. A star sometimes appears brighter and some other times fainter. What is this effect called? State the reason for
this effect.
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Answer 1

Answer:

A star sometimes appears brighter and some other times fainter, this effect is called as twinkling effect. This effect arises due to atmospheric refraction. Our atmosphere is constantly moving. Light travelling from thestars gets bent in different directions making them twinkle.

Explanation:

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Answer 2

Answer:

This effect is called Twinkling effect.

Reason: It is due to atmospheric refraction of starlight. The atmosphere has varying layers. The gradual change in the refractive index of different layers of atmosphere causes atmospheric refraction and starlight undergoes multiple refraction. So, the fluctuation in the position of star occurs continuously due to the changing amount of light entering the eye. The star sometimes appears brighter and at some other times, it appears fainter. This causes twinkling of star.