Question

Young's double slit experiment is carried out by using green, red and blue light, one colour at a time. The fringe widths recorded are $\beta_G,\beta_R$ and $\beta_B$ respectively. Then,

• A. $\beta_G > \beta_B > \beta_R$
• B. $\beta_B> \beta_G > \beta_R$
• C. $\beta_R > \beta_B > \beta_G$
• D. $\beta_R > \beta_G > \beta_B$

Answer 1

Answer: (D)

$\beta_R > \beta_G > \beta_B$

Answer 2

Fringe width $\beta =\frac{\lambda D}{d} \, \, or \, \, \, \beta ? \lambda$
Now, \hspace15mm \lambda_R > \lambda_G > \lambda_B
\therefore \hspace15mm \beta_R > \beta_G > \beta_B