- #1

Flucky

- 95

- 1

## Homework Statement

Light of wavelength λ is incident normally on a screen with a large array of slits having

equal widths

*b*, and periodically displaced by a distance

*a*.

(i) Find the maximum diﬀraction order which can be observed using this system of slits.

(ii) Find the minimum period a for which diﬀraction can be observed for light with

wavelength λ = 10µm.

## Homework Equations

AFAIK the only equation relevant is

*a*sinθ = mλ

One that has cropped up is sinθ

_{[itex]\pm1[/itex]}= [itex]\pm\frac{λ}{b}[/itex] , although there is no explanation next to this one so I'm not sure what it means.

## The Attempt at a Solution

Initial thoughts are to set θ = 90° as it's asking for a maximum. Past this I don't know where to go