Question 205: Waves Optics

Question

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).

Accepted Answer

For first minima
$$\begin{aligned}
& \operatorname{asin} 	heta=\lambda \
& \Rightarrow \sin 	heta=\frac{\lambda}{a}=\frac{5000 	imes 10^{-10}}{1 	imes 10^{-6}}=\frac{1}{2} \
& \Rightarrow 	heta=30^{\circ}
\end{aligned}$$

Waves Optics

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