Physics, asked by Krishna2456, 1 year ago

Give reason for the following:-

1 twinkling of stars
2 actual position of star
3 planets do not Twinkle why
4 advanced sunrise sunset

Answers

Answered by Anonymous
24
4.The Sun is visible to us two minutes before the sunrise and two minutes after the Sunset, because of the bending of the light due to atmospheric refraction. The light from the Sun got refracted by the atmospheric layers and reaches the observer. This causes the observer to think that the light is coming straight from the Sun.

1.....Stars twinkle because our atmosphere is constantly moving around or is turbulent. The light travelling from the stars gets bent in different direction making them twinkle. It is quite similar to the effect when viewing the reflection of the moon on a lake's surface when its (lake) moving.

3......Planets do not twinkle because they appear larger in size than the stars as they are relatively closer to earth. Planets can be considered as a collection of a large number of point-size sources of light. The different parts of these planets produce either brighter or dimmer effect in such a way that the average of brighter and dimmer effect is zero. Hence, the twinkling effects of the planets are nullified and they do not twinkle.

2.......The twinkling of stars is due to atmospheric refraction of starlight. Since the atmosphere bends starlight towards the normal the apparent position of the star is slightly different from its actual position. Hence the star appears slightly higher than its actual position.

HOPE IT HELPS YOU '_'
Answered by Nik1234
24
1. Stars are very distant, point sized sources. Path of light changes continuously due to changing of refractive index of the layers of air.Thus, the apparent position of the star fluctuates and the amount of starlight entering the eye fluctuates giving the twinkling effect.

2.The actual position of a star is different from the apparent position because of atmospheric refraction.

3.However the planets are nearer to us than stars, they appear to be comparatively larger, hence no twinkling is seen.

4.(a)Advanced sun rise- When the sun is slightly below the horizon, light rays coming from the sun travel from rarer to denser medium layers of air because of atmospheric refraction of light, light appears to come from a higher position above the horizon. Thus the sun appears earlier than actual sunrise.
 (b)Delayed sunset- Same reason as similar refraction occurs during sunset.

                                                     Hope this answer helped you :)
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