NEETPhysics-Wave Optics

NEET Physics Young's Double Slit Experiment MCQ Question

Type: MCQ-numerical-Medium-Class 12

A monochromatic light of frequency 500 THz is incident on the slits of a Young's double slit experiment. If the distance between the slits is 0.2 mm and the screen is placed at a distance 1 m from the slits, the width of 10 fringes will be:

A

5 mm

B

15 mm

C

30 mm

D

3 mm

Correct Answer

Option C

Detailed Explanation

The fringe width β is given by β = λD/d. Here, λ = c/f = 3 × 10⁸/500 × 10¹² m, D = 1 m, d = 0.2 × 10⁻³ m. Thus, β = 3 × 10⁸/500 × 10¹² × 1/0.2 × 10⁻³ = 3 mm. For 10 fringes, width = 10 × 3 = 30 mm.

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