Question

What will be the change in wave length, if a light of wave length 600 nm travels from air enters a medium of refractive index 1.5 and continues its journey through that medium?

• A. 300 nm
• B. 200 nm
• C. 600 nm
• D. 400 nm

Hint:

When light enters a medium with a refractive index greater than 1, its wavelength decreases proportionally to the refractive index.

Answer 1

The Correct Option is D

The wavelength of light changes when it passes from one medium to another, and this is governed by the refractive index. The relation between the wavelengths in two different media is given by: \[ \lambda_2 = \frac{\lambda_1}{n} \] where: - \( \lambda_1 \) is the wavelength of light in the first medium (air in this case), - \( \lambda_2 \) is the wavelength of light in the second medium, - \( n \) is the refractive index of the second medium. Given: - \( \lambda_1 = 600 \, \text{nm} \), - \( n = 1.5 \). Substitute the values into the formula: \[ \lambda_2 = \frac{600}{1.5} = 400 \, \text{nm} \] Thus, the wavelength of light after entering the medium with refractive index 1.5 is \( 400 \, \text{nm} \).