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CBSE notes-Light   Why does the sky appear dark instead of blue to an astronaut? The sky appears dark instead of blue to an astronaut because there is no atmosphere in the outer space that can scatter the sunlight. As the sunlight is not scattered, no scattered light reach the eyes of the astronauts and the sky appears black to them.

CBSE notes-Light A beam of red light is allowed to fall in turn on (a) a black cloth (b) red cloth (c) white cloth (d) blue cloth. Describe and explain the appearance in each case. (a) When red light falls on a black cloth it still appears black, because it does not reflect the red colour instead, it absorbs the light falling on it. (b) When red light falls on a red cloth it still appears red, because it reflects only that colour. (c) When red light falls on a white cloth it changes to a red coloured cloth, because the white cloth reflects the red colour of the light. (d) When red light falls on a blue cloth it changes to black coloured cloth, because there is no blue colour in the red light which can be reflected