Question

To an observer on the earth the stars appear to twinkle. This can be described by which of the following statements?

• A. Stars do not emit light continuously.
• B. Frequency of star light is absorbed by their own atmosphere.
• C. Frequency of star light is absorbed by the earth's atmosphere.
• D. Refractive index fluctuates in the earth's atmosphere.

Answer 1

Answer: (D)

Refractive index fluctuates in the earth's atmosphere.

Because of fluctuation of refractive index of earth's atmosphere, light rays from stars get refracted with different angle of refraction. That is why they seem twinkling.