Explain the experiment conducted by Newton to show that white light contains seven colours. Sun appears red in colour during sunrise but appears white at noon. Explain with the reasons.

Explain the experiment conducted by Newton to show that white light co

1.	Explain the experiment conducted by Newton to show that white light contains seven colours. Sun appears red in colour during sunrise but appears white at noon. Explain with the reasons.
Answer» Solution :(i) Newton allowed white light from the Sun to enter a dark room through a small APERTURE and placed the glass prism in the path of light RAYS. The light coming from the prism was received on white screen. On the screen a coloured patch like a rainbow was found which was termed as spectrum. The spectrum was found to be made of seven COLOURS VIBGYOR. From the above EXPERIMENT, Newton concluded that white light consists of seven colours. (i) At the lime of sunrise when the sun is near the horizon, the sunlight has to travel the larger distance through the atmosphere to REACH us. During this long journey of sunlight, most of the shorter wavelength blue-colour present in it is scattered out and away from our line of sight. So, the light reaching us at the lime of sunrise consists mainly of longer wavelength red colour due to which it appears to be red. (iii) At noon sun is overhead and light rays travel comparatively for smaller distance and only little ofblue/ violet light scatter, so sun appears white.