Question

Two slits are seperated by 0.320 mm. A beam of 500 nm light strikes the slits, producing an interference pattern. Determine the number of maxima observed in the angular range $-{30}^0<\theta <{30.0}^0$

Answer 1

$d\sin \theta =n\lambda$
$\sin \theta \times 32\times {10}^{-5}=\frac{n\times 500\times {10}^{-9}}{}$
$\sin \theta =\frac{n5}{3200}$
at $\theta ={30}^o$
$\frac{1}{2}=\frac{n5}{3200}$
$⟹n=\frac{1600}{5}$
$=320$
So there will be $320+ve,320-ve,1$ central
Total $=641$