Question

Calculate the speed of light in a medium whose critical angle is 45. Does critical angle for a given pair of media depend on the wavelength of incident light ? Give reason.

Answer 1

critical does not depend upon wavelength

Answer 2

SᎾᏞuᏆᎥᎾᏁ:

(i) According to the Snell's law, we have

μ = 1 ________(i)

sin C

where;

C = Critical angle of the medium

μ = Refractive index of the medium

Also,

μ = c __________(ii)

v

where;

c = Speed of light in vacuum

v = Speed of light in medium

__________________________

From (i) and (ii) we have

c = 1

sin C

=> v = sin C * c

=> v = sin 45° * 3 * 10^8

=> v = 2.12 * 10^8

Therefore speed of the light in medium is

2.12 * 10^8 ms^-1 ✅

_________________________

(i) we know that the critical angle of the medium depends on its refractive index.,which is given by,

C = sin^-1 ( 1/ μ)✅

Therefore the refractive index μ of the medium is

inversely proportional to the wave of incidence light.

So, the critical angle of the medium also depends upon wavelength of incident light.

_______________________(^•_•^)