In a single slit diffraction experiment, the angular width of central maximum is θ. If the entire apparatus is immersed in a liquid of refractive index n, the new angular width of the central maximum will become
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → θ/n
The angular width of the central maximum in single slit diffraction is proportional to the wavelength. In a liquid of refractive index n the frequency of light is unchanged but the wavelength is reduced by the factor n.
\( \displaystyle \theta = \frac{2\lambda}{a} \)
\( \displaystyle \lambda' = \frac{\lambda}{n} \)
\( \displaystyle \theta' = \frac{2\lambda'}{a} = \frac{2\lambda}{na} = \frac{\theta}{n} \)