The change of refractive index effects different factors of light in different waves. The major factors which change due to change in the refractive index are the speed of light and direction of the rays of light. The changes are explained as follows:
- Speed of light – In the last paragraph, we got an idea that if the refractive index of a medium is high, it is tough for light rays to pass through it. If it is so, some energy of light rays gets used up in the propagation through the medium. Due to this, the speed of light decreases in medium having a high refractive index. And similarly, if the medium is rarer or has a low refractive index, then the speed of light rays through that medium is high.
- Direction of propagation – Due to the change in speed, the direction of the light rays also changes according to the change in refractive density of the medium they are travelling through. If the light travels from a denser to rarer medium, the light rays move away from the normal to the surface of partition of the mediums. Similarly, if light rays travel from rarer to denser medium, then, the light rays move towards the normal to the surface of partition of the mediums.