Question

A light is travelling from air a medium the velocity of light in a medium is reduced to to 0.75 times the velocity n air assume that angle of incidence I is very small the deviation of the ray is
A. i
B. `(i)/(3)`
C. `(i)/(4)`
D. `(3i)/(4)`

Answer 1

Correct Answer - b
When a light travels from air into a medium then velocity of light in a medium is
`V_(m)=V-0.75 V= 0.25 V`
where v is velocity of light in air using snell law we have
`(sini)/(sin r)= mu =(v)/(v_(m))` or `(i)/(r )=(v)/(v_(m))`
or `(i)/(r )=(v)/(0.25 V)=4 rarr r=(i)/(4)`