Question

Green light (λ = 536 nm) strikes a single slit at normal incidence. What width slit will produce a central maximum that is 2.80 cm wide on a screen 1.70 m from the slit?

Answer 1

\[\sin\theta = \frac{\lambda}{a}\]
\[\tan\theta = \frac{max/2}{L}\]

Find the angle from the second equation (that's half the central maximum in the numerator)
Then use that angle in the first equation and solve for 'a', the slit width.