Physics - Diffraction | Olly Britton

Flashcards

What is diffraction?

The spreading out waves as it passes through an opening or aperture.

Why doesn’t shining a torch through a door frame cause diffraction?

Because the width of the door frame is very different from the wavelength.

When does diffraction occur?

When the width of the opening is roughly the same as the wavelength.

Why do radio waves travel further than micro waves?

Because radio waves can diffract around buildings and hills.

What happens to the wavelength of a wave as it is diffracted?

It stays the same.

What happens to the speed of a wave as it is diffracted?

It stays the same.

What happens to the frequency of a wave as it is diffracted?

It stays the same.

What is a diffraction grating?

An optical component with regularly spaced slits for separating light into beams of different wavelengths.

What is the equation for working out the wavelength $\lambda$ of the light of a maxima order $n$ at angle $\theta$ with slit separation $d$?

\[n\lambda = d \sin\theta\]

If there are 500 slits per millimeter in a diffraction grating, how could you work out the slit separation?

\[\frac{1\times10^{-3}}{500}\]

What is the maximum order of a maxima in a diffraction pattern described by $n\lambda = d\sin\theta$?

\[n = \frac{d}{\lambda}\]