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Question
During sunset and sunrise, the sun is seen when it is slightly below the horizon. Give reason.
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Solution
Light rays from the sun while coming towards earth suffers successive refractions from a rarer to a denser medium and so it bends towards the normal at each refraction. These rays on earth appear to be coming from an apparent position of the sun which is higher than its actual position. Thus, the sun is seen even when it is slightly below the horizon during sunset and sunrise.
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