The stars appear twinkling. The principle involved in it is
- refraction
- reflection
- total internal reflection
- dispersion
The Correct Option is A
Solution and Explanation
The twinkling of stars is due to the atmospheric refraction of light. As light from a star passes through the Earth's atmosphere, it encounters layers of air with varying temperatures and densities. These layers act like prisms, bending (refracting) the light. Since the atmosphere is constantly changing, the amount of bending varies continuously. This causes the star's apparent position and brightness to fluctuate, making it appear to twinkle.
Reflection is the bouncing back of light from a surface.
Total internal reflection occurs when light travels from a denser medium to a rarer medium at an angle of incidence greater than the critical angle. Dispersion is the splitting of white light into its constituent colors.
Top Questions on Refraction
- An air bubble is trapped at point P (CP = 1.75 cm) in a spherical glass ball (n = 1.5) of radius 7 cm as shown in the figure. Find the nature and position of the image when viewed from side B. Show the image formation by drawing a ray diagram.
Give reasons:
(i) The sky appears dark to passengers flying at very high altitudes.
At very high altitudes, passengers are above the atmosphere where there is less scattering of sunlight. As a result, they do not see the scattered blue light and the sky appears dark, similar to the condition experienced by astronauts in space.
(ii) 'Danger' signal lights are red in color.- CBSE Class X - 2025
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