Practice Diffraction in Physics

Use these practice problems to test your method after reviewing the concept explanation and worked examples.

Quick Recap

The spreading out of waves as they pass through a narrow opening or bend around the edges of an obstacle.

Waves 'bend around corners'—you can hear someone even if you can't see them.

Example 1

easy
Sound waves (\lambda = 1 \text{ m}) pass through a doorway 0.8 \text{ m} wide. Do the sound waves diffract significantly? Explain why you can hear someone around a corner.

Example 2

medium
Light of wavelength 600 \text{ nm} passes through a single slit of width 0.1 \text{ mm}. At what angle does the first minimum of the diffraction pattern occur?

Example 3

medium
Visible light (\lambda \approx 500 \text{ nm}) and radio waves (\lambda \approx 1 \text{ m}) both encounter a building 10 \text{ m} wide. Which wave diffracts more around the building? Why?

Example 4

hard
A diffraction grating has 500 \text{ lines/mm}. Light of wavelength 650 \text{ nm} passes through it. At what angle does the second-order maximum appear?
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