Question

A ray of light having wave length 3000 'A in a
medium having refractive index 1.4.The wave
length of same ray in air will be:
(a) 3000 °A (b) 6000'A
(C) 1500°A (d) 4200A​

Answer 1

Answer:

Here's Your Answer Mate..

Good Luck

Answer 2

Answer:

Option  d ) 4200 A

Explanation:

wavelength is inversely proportional to refractive index.

$n^{} \ \alpha\ \frac{1}{\lambda}$

let  $n_1$  and $n_2$ be the refractive indices of air and that medium.

Then $\lambda_1$ and $\lambda_2$  be the wavelength of the light in the air and that medium.

$\frac{n_1}{n_2} = \frac{\lambda_2}{\lambda_1}$

given:

$n_2$ = 1.4   ,  $\lambda_2$ = 3000 A  and we know that    $n_1$ = 1

so,

$\lambda_1 = \frac{\lambda_2 * n_2}{n_1}$

$\lambda_1 = 3000* 1.4$

$\lambda_1 = 4200A$