The Wave Equation (OCR A Level Physics): Revision Note
The Wave Equation
The wave equation links the speed, frequency and wavelength of a wave
This is relevant for both transverse and longitudinal waves
![Wave equation, downloadable AS & A Level Physics revision notes](https://cdn.savemyexams.com/cdn-cgi/image/f=auto,width=3840/https://cdn.savemyexams.com/uploads/2020/09/7.1.1.5-Wave-equation.png)
The wave equation shows that for a wave of constant speed:
As the wavelength increases, the frequency decreases
As the wavelength decreases, the frequency increases
![Frequency and wavelength, downloadable AS & A Level Physics revision notes](https://cdn.savemyexams.com/cdn-cgi/image/f=auto,width=3840/https://cdn.savemyexams.com/uploads/2020/09/7.1.1.5-Frequency-and-wavelength.png)
The relationship between frequency and wavelength of a wave
Worked Example
The wave in the diagram below has a speed of 340 m s–1.
![WE - Wave equation question image, downloadable AS & A Level Physics revision notes](https://cdn.savemyexams.com/cdn-cgi/image/f=auto,width=3840/https://cdn.savemyexams.com/uploads/2021/02/WE-Wave-equation-question-image.png)
What is the wavelength of the wave?
Answer:
![Worked example - wave equation, downloadable AS & A Level Physics revision notes](https://cdn.savemyexams.com/cdn-cgi/image/f=auto,width=3840/https://cdn.savemyexams.com/uploads/2020/09/7.1.1.5-Worked-example-wave-equation-e1615367280185.png)
Examiner Tips and Tricks
You may also see the wave equation be written as c = fλ where c is the wave speed. However, c is often used to represent a specific speed - the speed of light (3 × 108 m s-1). Only electromagnetic waves travel at this speed, therefore it’s best practice to use v for any speed that isn’t the speed of light instead.
You've read 0 of your 5 free revision notes this week
Sign up now. It’s free!
Did this page help you?