Light of wavelength $5000 \AA$ is incident normally on a slit of width $2.5 imes 10^{-4} \mathrm{~

Question

Light of wavelength $5000 \AA$ is incident normally on a slit of width $2.5 	imes 10^{-4} \mathrm{~cm}$. The angular position of second minimum from the central maximum is\

Professor PC Thomas Classes · Answer

B) Angular position of nth minimum from the central maximum is\ $\sin 	heta_{\mathrm{n}}=\frac{\mathrm{n} \lambda}{\mathrm{a}}$\ Here, $\lambda=5000 \mathrm{~A}^{0}=5 	imes 10^{-7} \mathrm{mg}$\ $\mathrm{a}=2.5 	imes 10^{-4} \mathrm{~cm}=2.5 	imes 10^{-6} \mathrm{~m}, \mathrm{n}=2$\ $	herefore \sin 	heta_{2}=\frac{2 	imes 5 	imes 10^{-7} \mathrm{~m}}{2.5 	imes 10^{-6} \mathrm{~m}}=\frac{2}{5}$\ or $	heta_{2}=\sin ^{-1}\left(\frac{2}{5}ight)$\