Question
The frequency of a light wave in the material is 2 x 10 Hz and wavelength is 5000 A. the refractive index of material will be:
-
1.40
-
1.50
-
3.00
-
1.33
Solution
C.
3.00
The velocity of light waves in the material is
ν = vλ ... (i)
Refractive index of material is
μ = c/v .... (ii)
where c is the speed of light in vacuum or air
Where c is speed of light in vacuum or air
or μ = c/vλ (iii)
Given, v = 2 x 1014 Hz,
λ = 5000 A = 5000 x 10-10 m,
c = 3x 108 m/s
Hence from Eq. (iii), we get
μ = 3 x 108 / 2 x 1014 x 500 x 10-10 = 3.00
