Using the wave speed equations
I can calculate the speed, frequency or wavelength of a wave using the wave equation.
- Year 10
- AQA
Using the wave speed equations
I can calculate the speed, frequency or wavelength of a wave using the wave equation.
Lesson details
Key learning points
- The speed of wave can be caluated using wave speed = frequency × wavelength.
- The speed of a wave can be caluated using wave speed = distance ÷ time.
- The choice of equation to use to caluate wave speed depends on the information provided in the question.
- Prefixes can be used with units to show very large or very small values.
- The frequency of a wave does not change as it crosses a boundary from one wave medium into another.
Keywords
Wave equation - wave speed = frequency × wavelength (v = f × λ)
Wave speed - The speed of a wave through a medium. Given by the wave equation: wave speed = frequency × wavelength (v = f × λ)
Frequency - The number of waves produced each second. Frequency is measured in Hertz (Hz)
Wavelength - The distance between one wave crest (or trough) and the next is the wavelength of the wave.
Prefix - A prefix is added to units to represent large or small values , for example 1 km = 1000 m and 1 mm = 0.001 m
Common misconception
In, v = f × λ, speed is dependent on frequency and wavelength, rather then the medium.
Focus on speed being property of a medium and equation not being as an equation with three interdependent variables.
Licence
Lesson video
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Prior knowledge starter quiz
6 Questions
Q1.What is the name for the number of vibrations a wave makes in a second?
Q2.What are the units for wave speed?
Q3.Which of these units cannot be used as a measure of wavelength?
Q4.What is an equivalent frequency of 330 000 Hz?
Q5.A transverse wave and a longitudinal wave have the same speed. Which statement about the waves is correct?
Q6.Put these prefixes in order starting with the smallest.
Assessment exit quiz
6 Questions
Q1.Which of these can cause the speed of a wave to change?
Q2.A wave has a wavelength of 1.5 m and a frequency of 5.0 Hz. What is its speed?
Q3.A wave in a rope has a wavelength of 0.3 m, and it travels with a wave speed of 1.5 m/s. Calculate the frequency of the wave.
Q4.A sound wave with a frequency of 150 Hz travels at 330 m/s in air. Calculate the wavelength of the wave.
