Explain the propagation of a ray of light, when it travels from rarer to denser medium.

Ans. 1. When the ray of light moves from an optically rarer medium to an optically denser medium, the ray bends towards the normal.

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2. In this case, the refractive index of the second medium is greater than the refractive index of the first medium.
3. The greater the value of refractive index, the more is the bending of refracted ray towards normal. The angle of incidence is greater than the angle of refraction.