The frequency of a light wave in a material is 2 x 10¹⁴ Hz and wavelength is 5000Å. The refractive index of material will be

Options

(a) 1.5
(b) 3
(c) 1.33
(d) 1.4

Correct Answer:

3

Explanation:

By using v = nλ , n = 2 x 10¹⁴ Hz
λ = 5000Å = 5000 x 10⁻¹⁰ m
v = 2 x 10¹⁴ x 5000 x 10⁻¹⁰ = 10⁸ m/s
Refractive index of the material,
µ = c / v = 3 x 10⁸ / 10⁸ = 3