Diffraction – Practice


1) A compressed air horn has a diameter of 5cm. What frequency of sound must be emitted if it is to diffract in a circular pattern?

2) The diagram below shows a wave with a wavelength of 25cm incident on a barrier with a gap of 15cm. If the frequency of the wave is increased and the gap remains unchanged explain how the diffraction through the gap will be affected:


3) A motion sensor emits a microwave signal through a gap of 2mm. What is the frequency of the emitted signal if it is going to create a circular diffraction pattern to spread through the room?

Quick Answers:

1) 6800 Hz

2) The diffraction pattern will become more circular

3) 1.5 × 1011 Hz

Worked Answers: