Consider the diffraction pattern obtained from the sunlight incident on a pinhole of diameter 0.1 μ m. If the diameter of the pinhole is slightly increased, it will affect the diffraction pattern such that: (a) its size increases, but intensity decreases (b) its size increases, and intensity increases (c) its size decreases, but intensity increases (d) its sizes decreases, and intensity decreases

Answer: (c). Angular size of the diffraction pattern ∝ (λ)/(d), so a larger pinhole gives a smaller pattern. A larger pinhole lets more light through, and it is spread over a smaller area, so intensity increases. So the answer is (c) size decreases, but intensity increases.

Consider the diffraction pattern obtained from the sunlight incident… | JEE Main 2021 (25 Feb, Shift 2)

Q60JEE Main 2021 · 25 FEB · SHIFT 2Easy

Diffraction at a Single Slit

Consider the diffraction pattern obtained from the sunlight incident on a pinhole of diameter 0.1 $\mu$ m. If the diameter of the pinhole is slightly increased, it will affect the diffraction pattern such that:

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Answer: (c)

Angular size of the diffraction pattern $\propto \dfrac{\lambda}{d}$ , so a larger pinhole gives a smaller pattern.
A larger pinhole lets more light through, and it is spread over a smaller area, so intensity increases.
So the answer is (c) size decreases, but intensity increases.

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Diffraction at a Single Slit question from JEE Main 2021 (25 Feb, Shift 2)

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