First slide

Diffraction

Question

A parallel beam of monochromatic light of wavelength 5000 $Å$ is incident normally on a single narrow slit of
width 0.001 mm. The light is focussed by a convex lens on a screen placed on focal plane. The first minimum will be formed for the angle of diffraction equal to

Moderate

A

0^o
B

15^o
C

30^o
D

45^o

Solution

For a narrow slit, d sin $θ = nλ$
$\sin θ = \frac{λ}{d} (∵ n = 1) or \sin θ = \frac{5000 \times 10^{- 10}}{0 \cdot 001 \times 10^{- 3}} = 0 \cdot 5 θ = \sin^{- 1} (0 \cdot 5) = \sin^{- 1} (1 / 2) = 30^{\circ}$

Get Instant Solutions

When in doubt download our app. Now available Google Play Store- Doubts App

Recieve an sms with download link

Doubts App

OR

SCAN ME

Doubts App

Doubts App