Question

A screen is placed 2m away from a single narrow slit. The slit width if the first minimum lies 5 mm on either side of the central maximum is:

(wave length $=$ 5000A${}^{\circ }$)

• A. $0.01cm$
• B. $0.02cm$
• C. $0.03cm$
• D. $0.04cm$

Answer 1

Answer: (B)

$0.02cm$

$x=\frac{\lambda \times D}{\omega }$
$\omega =\frac{\lambda \times D}{x}$
$=\frac{5000\times {10}^{-10}\times 2}{5\times {10}^{-3}}$
$=2\times {10}^{-4}m$
$=0.02cm$