IIT JEE , AIEEE Forum - Physics , Optics

srivathsan.v

One face of a prism is silver polished. A light ray falls at an angle of 45^o on the other face. After refraction, it is subsequently reflected from silver face and then retraverses its path. The angle of the prism is 30^o. What is its refractive index?

paddy.dude

as the beam is refelcted back along the same path
we can say that e=0
so in A+d=i+e we get,

30+d=45+0
d=15

now u can find ref index by applying the formula

n=sin(a+d/2)/sin a/2

srivathsan.v

the answer is root 2 and i'm not getting it

rakesh61

its simple let me explain

rakesh61

see to retrace its path the refracted ray has to fall perpebdiculat to the the 2 nd surface

so as per figure to get mew

we use snell law on first surface sin 45 / sin 30 and we get root over 2 which is the ans

Ask & Discuss Questions with Community & Experts