A beam of light is incident on a glass slab of refractive index 1.5 at an angle of incidence of 45o. Find the ratio of the width of refracted beam to the incident beam.

Explanation

As shown in the above figure distance travelled by the light ray through the slab is d From the figure
`cos r=t/d, d= t/ (cos r)`
Velocity of light in glass = `(Distance travell ed through the glass)/ (time) `
`c/mu= d/(time), time = (d mu)/c= (t mu )/ (cos r times c) = (mu^2 t)/ ( c sqrt(mu^2- sin^2 i))`