Question:
If the source of light used in a Young's double slit experiment is changed from red to violet :
Correct Option: 1
Solution:
$\beta=\frac{\lambda . D}{d}$
$\lambda_{\mathrm{R}}>\lambda_{\mathrm{V}}$
$\beta_{\mathrm{R}}=\frac{\lambda_{\mathrm{R}} \mathrm{D}}{\mathrm{d}}$ and $\beta_{\mathrm{V}}=\frac{\lambda_{\mathrm{V}} \mathrm{D}}{\mathrm{d}}$
$\beta_{\mathrm{R}}>\beta_{\mathrm{V}}$
Fringe pattern will shrink.
Option (1) is correct.