A parallel beam of monochromatic light of wavelength 5000 $\mathop A\limits^o$ is incident normally on a single narrow slit of width $0.001 \mathrm{~mm}$. The light is focused by convex lens on screen, placed on its focal plane. The first minima will be formed for the angle of diffraction of _________ (degree).
Answer (integer)
30
Solution
<p>For first minima</p>
<p>$$\begin{aligned}
& \operatorname{asin} \theta=\lambda \\
& \Rightarrow \sin \theta=\frac{\lambda}{a}=\frac{5000 \times 10^{-10}}{1 \times 10^{-6}}=\frac{1}{2} \\
& \Rightarrow \theta=30^{\circ}
\end{aligned}$$</p>
About this question
Subject: Physics · Chapter: Optics · Topic: Reflection and Mirrors
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