See now the thing is this: the angle between two refracting surfaces is called angle of the prism but in this diagram they had mentioned in my textbook that the angle of the prism is 90°. But by the R1+R2=A formula im not getting anything r1 is 0 r2 is 0
How to know which are the refracting surfaces I'm so confused how light is coming out of the third surface I understand it's suffering total internal reflection but there are only two refracting surfaces in a prism...
Now if im wrong then here they have taken angle of the prism as 30° then only by the formula R1+R2= A R1=0 then r2=30