Wavelength λ is the distance between a point on a wave and the same point on the next cycle of the wave, e.g. two crests or two troughs.

Amplitude A is the magnitude of the maximum displacement reached by an oscillation in the wave.

Frequency f is the number of complete wave cycles per second, measured in hertz (Hz) .

What is meant by the period of a wave?

The period T is the time taken for one complete oscillation at one point on the wave.

Waves are generated by .......... sources, whose disturbances travel away from the source.

Waves are generated by oscillating sources, whose disturbances travel away from the source.

True or False? All waves must travel through a medium.

False. Some waves, such as electromagnetic waves , can travel through a vacuum , while others need a medium such as air or water.

In the wave equation v = fλ , state what each symbol represents and its unit.

v = wave speed ( m s -1 ) f = frequency ( Hz ) λ = wavelength ( m )

For a wave travelling at constant speed, as the wavelength increases, the frequency .......... .

For a wave travelling at constant speed, as the wavelength increases, the frequency decreases .

True or False? At constant wave speed, frequency and wavelength are directly proportional.

False. At constant wave speed, frequency and wavelength are inversely proportional — as one increases, the other decreases.

Convert a frequency of 500 MHz into hertz (Hz).

500 MHz = 500 × 10 6 Hz = 5 × 10 8 Hz

Define longitudinal wave .

A longitudinal wave is one where the particles oscillate parallel to the direction of energy transfer and wave propagation.

A compression is a region of high pressure in a longitudinal wave.

A rarefaction is a region of low pressure in a longitudinal wave.

Give three examples of longitudinal waves .

Sound waves Ultrasound waves P-waves produced by earthquakes

In a longitudinal wave, the particles oscillate .......... to the direction of energy transfer.

In a longitudinal wave, the particles oscillate parallel to the direction of energy transfer.

True or False? Longitudinal waves can be polarised.

False. Longitudinal waves cannot be polarised; only transverse waves can be polarised.

Define transverse wave .

A transverse wave is one where the particles oscillate perpendicular to the direction of energy transfer and wave propagation.

Give three examples of transverse waves .

Electromagnetic waves (e.g. radio, visible light, UV) Vibrations on a guitar string Waves on a rope or slinky

In a transverse wave, the particles oscillate .......... to the direction of energy transfer.

In a transverse wave, the particles oscillate perpendicular to the direction of energy transfer.

True or False? Transverse waves cannot be polarised.

False. Transverse waves can be polarised — this is a key property that distinguishes them from longitudinal waves.

How is wavelength measured on a displacement-distance graph?

From one point on the wave to the same point on the next wave, e.g. between two consecutive crests or troughs .

Which two graphs can represent a longitudinal wave ?

Displacement-distance graphs and pressure-distance graphs.

For a longitudinal wave, the pressure-distance graph is .......... out of phase with the displacement-distance graph.

For a longitudinal wave, the pressure-distance graph is 90° out of phase with the displacement-distance graph.

At a compression in a sound wave, what is the displacement of the air molecules and the pressure?

The air molecules have zero displacement from their equilibrium positions, and the region is at high pressure .

True or False? A sinusoidal graph must represent a transverse wave.

False. A longitudinal wave can also look sinusoidal when plotted; check whether the wave travels parallel (longitudinal) or perpendicular (transverse) to its direction of travel.

What is produced when a wave is reflected with a 180° phase difference?

A stationary (standing) wave , made up of a series of nodes and antinodes .

What is measured in Core Practical 6: Investigating the Speed of Sound?

The speed of sound in air , using an oscilloscope and a signal generator .

State the independent and dependent variables for this experiment.

Independent variable: distance Dependent variable: phase of the received signals

The frequency should be found from the .......... of the oscilloscope rather than the dial of the signal generator.

The frequency should be found from the time base of the oscilloscope rather than the dial of the signal generator.

How can random errors be reduced in this experiment?

Take repeat readings and average them, and make the distance between the microphone and signal generator as large as practical .

True or False? The accuracy of this experiment is limited by the experimenter's reaction time.

False. The timing is done automatically by the oscilloscope, so reaction time is not a factor — this makes the experiment very accurate.

A LevelPhysicsEdexcelFlashcards5. Waves & Particle Nature of LightTransverse & Longitudinal Waves

Transverse & Longitudinal Waves (Edexcel A Level Physics): Flashcards

Exam code: 9PH0

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FrontProperties of Waves
Define wavelength.

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Cards in this collection (37)

Define wavelength.
Wavelength λ is the distance between a point on a wave and the same point on the next cycle of the wave, e.g. two crests or two troughs.
Define amplitude.
Amplitude A is the magnitude of the maximum displacement reached by an oscillation in the wave.
Define frequency.
Frequency f is the number of complete wave cycles per second, measured in hertz (Hz).
What is meant by the period of a wave?
The period T is the time taken for one complete oscillation at one point on the wave.
State the symbol and SI unit for wave speed.
Symbol: c. Unit: m s^-1.
Waves are generated by .......... sources, whose disturbances travel away from the source.
Waves are generated by oscillating sources, whose disturbances travel away from the source.
True or False?
All waves must travel through a medium.
False.
Some waves, such as electromagnetic waves, can travel through a vacuum, while others need a medium such as air or water.
State the wave equation.
$v = f λ$
where v is the wave speed, f is the frequency and λ is the wavelength.
In the wave equation v = fλ, state what each symbol represents and its unit.
v = wave speed (m s^-1)
f = frequency (Hz)
λ = wavelength (m)
For a wave travelling at constant speed, as the wavelength increases, the frequency ...........
For a wave travelling at constant speed, as the wavelength increases, the frequency decreases.
True or False?
At constant wave speed, frequency and wavelength are directly proportional.
False.
At constant wave speed, frequency and wavelength are inversely proportional — as one increases, the other decreases.
How do you calculate wavelength from wave speed and frequency?
Rearrange the wave equation:
$λ = \frac{v}{f}$
Convert a frequency of 500 MHz into hertz (Hz).
500 MHz = 500 × 10⁶ Hz = 5 × 10⁸ Hz
Define longitudinal wave.
A longitudinal wave is one where the particles oscillate parallel to the direction of energy transfer and wave propagation.
Define compression.
A compression is a region of high pressure in a longitudinal wave.
Define rarefaction.
A rarefaction is a region of low pressure in a longitudinal wave.
Give three examples of longitudinal waves.
Sound waves
Ultrasound waves
P-waves produced by earthquakes
In a longitudinal wave, the particles oscillate .......... to the direction of energy transfer.
In a longitudinal wave, the particles oscillate parallel to the direction of energy transfer.
True or False?
Longitudinal waves can be polarised.
False.
Longitudinal waves cannot be polarised; only transverse waves can be polarised.
Define transverse wave.
A transverse wave is one where the particles oscillate perpendicular to the direction of energy transfer and wave propagation.
What two features are seen on a transverse wave?
Crests (peaks) and troughs.
Give three examples of transverse waves.
Electromagnetic waves (e.g. radio, visible light, UV)
Vibrations on a guitar string
Waves on a rope or slinky
In a transverse wave, the particles oscillate .......... to the direction of energy transfer.
In a transverse wave, the particles oscillate perpendicular to the direction of energy transfer.
True or False?
Transverse waves cannot be polarised.
False.
Transverse waves can be polarised — this is a key property that distinguishes them from longitudinal waves.
How is wavelength measured on a displacement-distance graph?
From one point on the wave to the same point on the next wave, e.g. between two consecutive crests or troughs.
On a displacement-time graph, what does one full cycle represent, and how is frequency found?
One full cycle represents the period T. Frequency is found using:
$f = \frac{1}{T}$
Which two graphs can represent a longitudinal wave?
Displacement-distance graphs and pressure-distance graphs.
For a longitudinal wave, the pressure-distance graph is .......... out of phase with the displacement-distance graph.
For a longitudinal wave, the pressure-distance graph is 90° out of phase with the displacement-distance graph.
At a compression in a sound wave, what is the displacement of the air molecules and the pressure?
The air molecules have zero displacement from their equilibrium positions, and the region is at high pressure.
True or False?
A sinusoidal graph must represent a transverse wave.
False.
A longitudinal wave can also look sinusoidal when plotted; check whether the wave travels parallel (longitudinal) or perpendicular (transverse) to its direction of travel.
What is produced when a wave is reflected with a 180° phase difference?
A stationary (standing) wave, made up of a series of nodes and antinodes.
What is measured in Core Practical 6: Investigating the Speed of Sound?
The speed of sound in air, using an oscilloscope and a signal generator.
State the independent and dependent variables for this experiment.
Independent variable: distance
Dependent variable: phase of the received signals
Which equations are used to find the speed of sound in this practical?
$v = f λ$
with the frequency found from the oscilloscope trace using:
$f = \frac{1}{T}$
The frequency should be found from the .......... of the oscilloscope rather than the dial of the signal generator.
The frequency should be found from the time base of the oscilloscope rather than the dial of the signal generator.
How can random errors be reduced in this experiment?
Take repeat readings and average them, and make the distance between the microphone and signal generator as large as practical.
True or False?
The accuracy of this experiment is limited by the experimenter's reaction time.
False.
The timing is done automatically by the oscilloscope, so reaction time is not a factor — this makes the experiment very accurate.

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