NEET2019Physics-Wave Optics

NEET 2019 Physics Young's Double Slit Experiment MCQ Question

Type: MCQ-conceptual-Medium-Class 12

In a double slit experiment, when light of wavelength 400 nₘ was used, the angular width of the first minima formed on a screen placed 1 m away, was found to be 0.2°. What will be the angular width of the first minima, if the entire experimental apparatus is immersed in water? (μwater = 4/3)

A

0.05°

B

0.10°

C

0.26°

D

0.15°

Correct Answer

Option D

Detailed Explanation

The angular width of the first minima is given by θ = λ/d. When immersed in water, the wavelength becomes λ/n. Thus, θ' = λ/(nd). The new angular width is 0.2°/1.33 = 0.15°.

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