Chapter 45: Problem 21

Question: Light of wavelength $\lambda~=~600~{\rm nm}$ is incident normally on two paralle slits separated by $d~=~0.60~{\rm mm}$. Sketch the intensity pattern observed on a distant screen as a function of angle $\theta$for the range of values $0<\theta<0.0040~{\rm radians}$.

Solution: Maximia occur for $d\sin\theta~=~m\lambda$, which means $\sin\theta~=~m 10^{-3}$. The intensity pattern behaves as $\cos^2\left({\pi d\sin\theta\over\lambda}\right)$.