By Team Aakash Byju's

Derive The Formula For Angle Of Minimum Deviation For The Prism

We derive the formula and learn what are the terms used in the formula.

The angle of minimum deviation is given as:

The minimum angle at which the angle of incidence and the angle of emergence are equal is called the Angle of Minimum Deviation.

Consider the labelled diagram to begin the derivation.

i1 is the angle of incidence whereas i2 is the angle of emergence. OP and QR are the incident and emergent rays respectively.

A - Prism angle and  angle of deviation and we know that for minimum deviation  r1 = r2 = r. Therefore,

Also, for minimum deviation

So, A +  = i1 + i2 becomes