# Refractive index = #sin i/sin r# or #sin r/sin i#. what does it tell? and ABOUT WHAT?

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I have known the formula refractive index = Speed of light in vacuum/ speed of light in specific medium.

or simply #n=c/v# . Is there any difference between these two? if yes the please explain.

I have known the formula refractive index = Speed of light in vacuum/ speed of light in specific medium.

or simply

##### 1 Answer

The equations are equivalent - the angle through which the light will bend will depend on the relative speeds in the two media.

#### Explanation:

The more the light slows down the greater the angle it turns through i.e the greater the difference between sin i and sin r and therefore the greater the refractive index. Think of a car going from a motorway into a level field at an angle. The wheel that enters the filed first will slow down and the faster movement of the rest of the wheels will make the car turn - the greater the difference in speed, the more it will turn...