Question

Fringe width observed in the Young's double slit experiment is b. If the frequency of the source is doubled, the fringe width will –

• A. Remain b
• B. Become b/2
• C. Become 2b
• D. Remain 3b/2

Answer 1

Answer: (B)

Become b/2

Answer 2

Width of fringe = b

if frequency is doubled then, wavelength becomes halved, because velocity of light in air remain same

b µ l ̃ $\frac{\beta'}{\beta}$= $\frac{\lambda'}{\lambda}$= $\frac{\lambda/2}{\lambda}$= $\frac{1}{2}$ $\begin{matrix} \beta' = \frac{\beta}{2} \end{matrix}$