Home › Maharashtra SSC (Class 10) › Physics › Refraction of Light › What is the main reason that stars appear to twi…
What is the main reason that stars appear to twinkle when viewed at night?
APeriodic explosions occurring inside the distant stars
BThe actual rapid motion of the stars across the sky
CThe continuously changing refractive index of the air
DAbsorption of starlight by the dense lower atmosphere
Answer & Solution
Correct answer: C. The continuously changing refractive index of the air
1. Stars are so distant they behave as point sources of light.
2. Atmospheric air is in motion and its density and temperature keep changing, so the refractive index of air changes continuously.
3. The chapter states that because of this changing refractive index, the position and brightness of the star keep changing and it appears to twinkle.
4. Explosions, stellar motion and absorption are not the stated cause, so they are rejected.
_Source: Balbharati (Maharashtra Board) Class 10 Science & Technology, Ch 6 "Refraction of Light", p.85_
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 cPlanets, unlike stars, do not appear to twinkle. What is the reason given in the chapter?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