Angular width of central maximum $= \frac{2\lambda}{a}$
$$0.1 = \frac{2\lambda}{a} \Rightarrow \lambda = \frac{0.1a}{2} = \frac{a}{20}$$
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JEE Main 2023 — Physics Optics
hard
mcq
2023
Official previous-year question
Verified 30 May 2026.
Question
In a single slit diffraction pattern, the angular width of the central maximum is $0.1\,\text{rad}$. If the slit width is $20\lambda$, the value of $\lambda$ in terms of slit width $a$ is:
Options
- A
$\frac{a}{10}$
- B
$\frac{a}{20}$
- C
$\frac{a}{40}$
- D
$\frac{a}{5}$
Solution
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