Physics
Assertion (A): The stars twinkle while the planets do not.
Reason (R): Stars are more distant than the planets.
- Both A and R are true and R is the correct explanation of A.
- Both A and R are true and R is not the correct explanation of A.
- assertion is false but reason is true.
- assertion is true but reason is false.
Refraction Plane Surfaces
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Answer
1. Both A and R are true and R is the correct explanation of A.
Explanation
Assertion (A) is true. Planets do not twinkle because, unlike stars, they are seen as extended sources of light. When observing a planet, which appears as a disk rather than a point of light, the combined effect of a large number of point-sized sources averages out the total variation in the amount of light entering the observer's eye. This averaging effect nullifies the twinkling phenomenon, making planets appear steady in brightness.
Reason (R) is true. Planets are much closer to us than stars, so they are not point-sized objects to our eye. Hence, the fluctuations have a negligible effect and they don't seem to twinkle.
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