Home › Maharashtra SSC (Class 10) › Physics › Refraction of Light › Planets, unlike stars, do not appear to twinkle.…
Planets, unlike stars, do not appear to twinkle. What is the reason given in the chapter?
AThey lie entirely outside the refracting layers of the earth's atmosphere
BThey are self-luminous and emit their own perfectly steady continuous light
CTheir reflected light is not refracted by the atmosphere at any point
DThey are close, so appear as many point sources whose average brightness stays steady
Answer & Solution
Correct answer: D. They are close, so appear as many point sources whose average brightness stays steady
1. The chapter explains that planets are much closer to us than stars.
2. Because of this, they appear not as single points but as a collection of point sources.
3. Atmospheric refraction changes each point's position and brightness, but the average position and total brightness remain unchanged, so planets do not twinkle.
4. Planets are not self-luminous (they reflect sunlight) and their light is still refracted, so those distractors are false.
_Source: Balbharati (Maharashtra Board) Class 10 Science & Technology, Ch 6 "Refraction of Light", p.86_
Related questions
A mirage on a hot road forms because the air near the hot surface is rarer than the air abWhen a monochromatic light ray passes through a parallel-sided glass slab from air, how doA rainbow seen after rainfall is produced by water droplets acting as tiny prisms. Which cWhat is the main reason that stars appear to twinkle when viewed at night?We are able to see the Sun even when it is a little below the horizon at sunrise and sunseFor total internal reflection, with i equal to the critical angle and r equal to 90 degreeTotal internal reflection of light can occur only when light is travelling under which of When the angle of incidence in the denser medium equals the critical angle, what is the an