Question

Sunset is red because at that time the light coming from the sun has to travel:
(a) lesser thickness of earth's atmosphere
(b) greater thickness of earth's atmosphere
(c) varying thickness of earth's atmosphere
(d) along the horizon

Answer 1

 greater thickness of the earth's atmosphere

The sun appears red at sunset because, at that time, the sun is near the horizon and, therefore, sunlight has to travel through a greater thickness of the earth's atmosphere.