wiz-icon
MyQuestionIcon
MyQuestionIcon
1
You visited us 1 times! Enjoying our articles? Unlock Full Access!
Question

A parallel beam of light of wavelength 6000 ˙A is incident normally on a slit of width 0.2 mm. The diffraction pattern is observed on a screen which is placed at the focal plane of a convex lens of focal length 50 cm. If the lens is placed close to the slit. The distance between the minimum on both sides of the central maximum will be

A
1 mm
No worries! We‘ve got your back. Try BYJU‘S free classes today!
B
3 mm
Right on! Give the BNAT exam to get a 100% scholarship for BYJUS courses
C
2 mm
No worries! We‘ve got your back. Try BYJU‘S free classes today!
D
4 mm
No worries! We‘ve got your back. Try BYJU‘S free classes today!
Open in App
Solution

The correct option is B 3 mm
Given:
λ=6000 ˙A
b=0.2 mm=0.2×103 m
f=50 cm=0.5 m

The angular position of first minima from the central maximum is given by,

sinθ=λb=6000×10100.2×103

sinθ=3×103

For small θ, sinθθ

θ=3×103 rad

If the lens is placed close to the slit, then

tanθθ=xf

Where, x is the distance of first minimum from the central maximum.

Therefore, the distance between two minima on both sides of the central maximum is

2x=2fθ=2×0.5×3×103

2x=3 mm

Hence, option (C) is correct.

flag
Suggest Corrections
thumbs-up
0
Join BYJU'S Learning Program
similar_icon
Related Videos
thumbnail
lock
Fringe Width
PHYSICS
Watch in App
Join BYJU'S Learning Program
CrossIcon