Diffraction (T3) Flashcards
What is diffraction and how does it work?
When a wave meets a gap in a barrier it will carry on through that gap however it will spread out to some extent into the area beyond the gap.
This is diffraction.
The amount of diffraction depends on the wavelength and the size of the gap.
The extent of the spreading depends on the width of the gap compared with the wavelength of the waves.
The smaller the width of the gap compared with the wavelength, the stronger the diffraction.
How is sound diffracted?
Sound can diffract through a doorway or around buildings.
Lower pitched sounds travel better than high pitched sounds.
This is because lower pitched sounds have a long wavelength compared to the width of the gap so they spread out more.
Describe how ultrasound is diffracted..
Ultrasound is a sound with very high frequency and it has a very short wavelength compared with most gaps so there is very little spreading out.
This makes sharp focusing of ultrasound easier, which is good for medical scanning.
Describe how light is diffracted..
Light has a very short wavelength compared with most everyday gaps such as windows and doors.
There is little obvious diffraction so it produces sharp shadows.
Describe how radio waves are diffracted…
Long wave radio signals are much less affected by buildings and tunnels than short wave radio signals or VHF radio signals.
Because of diffraction, radio signals can sometimes be received in the shadows of hills.
