Light is incident at a small angle on a plane boundary separating two transparent…

PHYSICS · Multi-part · A Level · Physics · Waves · Waves

Problem

Light is incident at a small angle on a plane boundary separating two transparent media of refractive indices

n_1

and

n_2

(

n_2>n_1

). (a) Using the small-angle approximation (

\sin \theta \approx \theta

in radians), derive an approximate relation showing that the angle of refraction

r

\dfrac{n_1}{n_2}\,i

, where

i

is the angle of incidence. (b) Light from air (

n_1=1.00

) enters flint glass (

n_2=1.52

) with

i=0.10\,\text{rad}

. Calculate the corresponding value of

r

(to two significant figures).