Question

All the same angle of incidence in media A B and C the angles of refraction are 20 degree 30 degree and 40 degree respectively in which medium will the velocity of light be maximum give reason in support of your answer

Answer 1

Hey mate,

Here is ur answer.

I took it from the marking scheme of cbse sample paper.

Hope it helps.....

Answer 2

speed of the ray of light will be max in medium 3 and min in medium 1

we know that for any given pair of media from snell's law,

₂μ₁=sin i/sin r,

since the angle of incidence is same for all the cases we consider it to be i, now the μ for different media can be be expressed as,

μ₁=sin i/sin 20

μ₂=sin i/sin 30

μ₃=sin i/sin 40

since the value of sin 20<sin 30<sin 40,

the μ₁>μ₂>μ₃...now from cauchy's formula we get the relation that μ is inversely proportional to wavelength

so λ₁<λ₂<λ₃ and we know speed =frequency *wavelength,speed∝λ therefore speed in medium 3 will be max