Question

A light ray of frequency $\nu$ and wavelength $\lambda$ enters a liquid of refractive index $\dfrac{3{2}$. The ray travels in the liquid with}

• A. frequency $\nu$ and wavelength $\dfrac{1}{2}\lambda$
• B. frequency $\nu$ and wavelength $\dfrac{2}{3}\lambda$
• C. frequency $\dfrac{3}{2}\nu$ and wavelength $\lambda$
• D. frequency $\nu$ and wavelength $\dfrac{3}{2}\lambda$

Hint:

Frequency of light never changes during refraction; only speed and wavelength change.

Answer 1

The Correct Option is B

Step 1: Effect of refraction on frequency.
When light enters a medium, its frequency remains unchanged.

Step 2: Relation between wavelength and refractive index.
\[ n = \frac{\lambda}{\lambda'} \]

Step 3: Calculate wavelength in the liquid.
\[ \lambda' = \frac{\lambda}{n} = \frac{\lambda}{3/2} = \frac{2}{3}\lambda \]

Step 4: Conclusion.
The light travels with frequency $\nu$ and wavelength $\dfrac{2}{3}\lambda$.