Question

Twinkling of stars is on account of
(a). Large distance of stars and storms in air
(b). Small size of stars
(c). Large size of stars
(d). Large distance of stars and fluctuations in density of the air

Answer 1

- Hint- In order to deal with this question first we will under the basic concept of twinkling of stars then we will proceed further by checking for all the options provided.

Complete step-by-step solution -

The stars twinkle in the night sky because of the effects of our atmosphere. When starlight enters our atmosphere it is affected by winds in the atmosphere and by areas with different temperatures and densities. This causes the light from the star to twinkle when seen from the ground.
The twinkling of stars is due to atmospheric refraction of star-light. The refraction of light caused by the earth's atmosphere having air layers of varying optical density is called atmospheric refraction.
The physical conditions of the atmosphere keep on changing continuously due to which density of air in different layers of atmosphere also keeps on changing.
As a result of this, the refractive index of the various layers of atmosphere also keeps on changing continuously. So, light coming from stars suffers multiple refractions and the amount of starlight reaching the eye also keeps changing and so, due to fluctuation of perceived brightness of the star, they appear like they are twinkling.

Hence, twinkling of stars is on account of the large distance of stars and fluctuations in density of the air.
So, the correct answer is option D.

Note- Atmospheric refraction is the deviation of light or other electromagnetic wave from a straight line as it passes through the atmosphere due to the variation in air density as a function of height. This refraction is due to the velocity of light through air, decreasing with increased density.