# Physics - Diffraction

> Source: https://ollybritton.com/notes/a-level/physics/topics/diffraction/ · Updated: 2021-03-11 · Tags: physics, school, waves, year-1

## See Also
- [Physics - Reflection and Refraction](https://ollybritton.com/notes/a-level/physics/topics/reflection-and-refraction/)

## Flashcards
### 2021-03-11
##### What is diffraction??
The spreading out waves as it passes through an opening or apeture.

##### 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.

### 2022-02-07
##### What is a diffraction grating??
An optical component with regularly spaced slits for seperating 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 s lit seperation $d$??
$$
n\lambda = d \sin\theta
$$

##### If there are 500 slits per millimeter in a diffraction grating, how could you work out the slit seperation??
$$
\frac{1\times10^{-3}}{500}
$$

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

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