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

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.

1 Answer
Jun 28, 2016

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


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...