Home · A-Level 9702 · Superposition · Diffraction · Practice
AS · Practice questions · Diffraction

Bending round edges.

Six original Cambridge-style questions on diffraction and the gap-to-wavelength ratio.

Original questions All questions on this page are original work, written in the Cambridge AS & A Level style. They are not from past papers. They test the same concepts and skills the syllabus rewards.
Keep these straight

Gap near the wavelength.

01
Analysis
[2 marks]

Define diffraction.

  • Diffraction is the spreading of a wave as it passes through a gap or travels around the edge of an obstacle ✓
02
Analysis
[2 marks]

State the condition on the gap width for diffraction to be most pronounced.

  • The gap width should be about the same as the wavelength of the wave ✓
03
Analysis
[2 marks]

Explain why light usually casts sharp shadows while sound bends around corners.

  • Light has a very short wavelength compared with everyday gaps, so it diffracts very little and casts sharp shadows ✓
  • Sound has a much longer wavelength, comparable to doorways, so it diffracts strongly and spreads around corners ✓
04
Analysis
[2 marks]

State the effect, if any, of diffraction on the wavelength, frequency and speed of a wave.

  • Diffraction changes only the direction in which the wave spreads ✓
  • The wavelength, frequency and speed are all unchanged ✓
05
Analysis
[2 marks]

In a ripple tank, describe what happens to the diffracted waves as the gap is gradually narrowed toward one wavelength.

  • The waves spread out more and more ✓
  • until, at a gap of about one wavelength, they spread into almost semicircular wavefronts ✓
06
Analysis
[2 marks]

Diffraction is a property of all waves. Name three different types of wave that diffract.

  • For example: sound waves, light (electromagnetic) waves and water waves ✓
  • (microwaves and other waves also diffract) ✓

Mark this once you have attempted all six and checked your working. It records a Practiced badge on the topic and adds a one-time bonus. Revealing the solutions alone does not count.