1. Describing transverse waves and the wave equation
Lesson Objectives:
To be able to identify amplitude, wavelength and frequency on a diagram of a transverse wave.
To be able to use the equation for wave speed
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2. JCX - Y11 W+R
REMEMBER LAST LESSON….
We cannot see light or sound waves so looking at waves moving along a spring can help us learn more about them.
There are 2 main types of waves, they carry a lot of energy from one place to another.
The 2 types are called TRANSVERSE AND LONGITUDINAL waves.
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3. TRANSVERSE AND LONGITUDINAL
TRANSVERSE WAVES
The wave moves at right angles to the disturbance or vibration.
LONGITUDINAL WAVES
The wave moves along in the same direction as the disturbance or vibration.
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4. Vibration Direction of travel Wavelength Amplitude Amplitude
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5. Vibration Direction of travel Wavelength – Peak to Peak Wavelength –
Trough to Trough
Direction of travel
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6. Height (m)
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Frequency – The number of waves per second. If one wave passes in one second it has a frequency of one Hertz or Hz. This is the unit of frequency. 2 1
Time (s) 1 2 1 2
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7. How fast do waves travel?
You can work out the speed of a wave if you know…..
1. How many waves pass each second.
(the frequency).
2. How long each wave is.
(the wavelength)
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8. The wave equation WAVE SPEED = FREQUENCY X WAVELENGTH (m/s) (Hz) (m)
Hz is short for HERTZ which is the unit of measurement for frequency.
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9. The wave equation Wave speed = frequency x wavelength
Example:
Frequency = 165Hz
Wavelength = 2m
What is the wave speed?
Wave speed = frequency x wavelength
Wave speed = Hz x 2m
Wave speed = m/s
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10. 1) Wavelength = 3m, Frequency = 100Hz
Find the wave speeds….
1) Wavelength = 3m, Frequency = 100Hz
2) Wavelength = 2m, Frequency = 135Hz
3) Wavelength = 0.5m, Frequency = 200Hz
Remember the 3 step method for equations – YOU MUST DO THIS TO GET FULL EXAM MARKS!!
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11. m/s
Wave speed
Using your formula triangle means you can work out what equation to use if you need to find wavelength and frequency.
Frequency x
wavelength m Hz
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12. Further Work Complete questions................from your text book.
HOMEWORK
How could you measure the speed of water waves. Plan an investigation to show how this can be done.
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