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Waves in matter: GCSE questions with answers

21 physics questions on waves in matter. Pick your answer, then tap to see if you were right and why. Every answer comes from the Show Working science bank, checked against the GCSE content every board in England teaches.

Quiz yourself: 21 questions 2 6-mark questions

01 / Quiz yourselfTry it, then tap to check

Waves in matter questions to try

Choose your answer before you open it. Then read why, so it sticks.

01 / Waves in matterBoth tiers

What is the amplitude of a wave?

  1. AThe height from a peak down to a trough
  2. BIts maximum displacement from the rest position
  3. CThe number of waves passing a point each second
  4. DThe distance from one peak to the next
Show the answer

Answer: B Its maximum displacement from the rest position

The amplitude is how far a point on the wave moves from its undisturbed (rest) position, at most. It is measured from the middle line to a peak, not from a peak to a trough, which would be twice the amplitude.

Checked against AQA GCSE Physics 8463 specification, 4.6.1.1 and 4.6.1.2 Transverse and longitudinal waves, properties of waves

02 / Waves in matterBoth tiers

What is the wavelength of a wave?

  1. AThe distance from a point on one wave to the same point on the next
  2. BThe height of a peak above the rest position
  3. CThe time taken for one complete wave to pass
  4. DThe distance from a peak to the next trough
Show the answer

Answer: A The distance from a point on one wave to the same point on the next

Wavelength is the length of one whole wave: from one peak to the next peak, or from any point to the matching point on the next wave. It is a distance, so it is measured in metres.

Checked against AQA GCSE Physics 8463 specification, 4.6.1.1 and 4.6.1.2 Transverse and longitudinal waves, properties of waves

03 / Waves in matterBoth tiers

What is the frequency of a wave?

  1. AThe distance between two neighbouring peaks
  2. BThe height of a peak above the rest position
  3. CThe number of waves passing a point each second
  4. DThe time taken for one complete wave to pass
Show the answer

Answer: C The number of waves passing a point each second

Frequency counts how many whole waves pass a point (or are made by the source) every second. It is measured in hertz: 1 Hz means one wave each second.

Checked against AQA GCSE Physics 8463 specification, 4.6.1.1 and 4.6.1.2 Transverse and longitudinal waves, properties of waves

04 / Waves in matterBoth tiers

What is the period of a wave?

  1. AThe distance between two neighbouring peaks
  2. BThe number of waves passing a point each second
  3. CThe time for one complete wave to pass a point
  4. DThe height of a wave from the rest position
Show the answer

Answer: C The time for one complete wave to pass a point

The period is the time for one whole wave. Period = 1 ÷ frequency, so a wave with a higher frequency has a shorter period: doubling the frequency halves the period.

Checked against AQA GCSE Physics 8463 specification, 4.6.1.1 and 4.6.1.2 Transverse and longitudinal waves, properties of waves

05 / Waves in matterBoth tiers

Which equation links wave speed, frequency and wavelength?

  1. AWave speed = wavelength ÷ frequency
  2. BWave speed = frequency ÷ wavelength
  3. CWave speed = amplitude × frequency
  4. DWave speed = frequency × wavelength
Show the answer

Answer: D Wave speed = frequency × wavelength

Wave speed = frequency × wavelength (v = f λ), with speed in m/s, frequency in Hz and wavelength in m. If the speed stays the same, frequency and wavelength are inversely proportional: double one and the other halves.

Checked against AQA GCSE Physics 8463 specification, 4.6.1.1 and 4.6.1.2 Transverse and longitudinal waves, properties of waves

06 / Waves in matterBoth tiers

What does the speed of a wave tell you?

  1. AHow fast energy is carried through the medium
  2. BHow far each particle moves from its rest position
  3. CHow long one complete wave takes to pass
  4. DHow many waves pass a point each second
Show the answer

Answer: A How fast energy is carried through the medium

Wave speed is the speed at which the wave, and the energy it carries, moves through the medium. It is measured in metres per second, like any other speed.

Checked against AQA GCSE Physics 8463 specification, 4.6.1.1 and 4.6.1.2 Transverse and longitudinal waves, properties of waves

07 / Waves in matterBoth tiers

In a transverse wave, how are the oscillations arranged?

  1. AAt 45° to the direction of energy transfer
  2. BAt right angles to the direction of energy transfer
  3. CIn random directions that keep changing
  4. DParallel to the direction of energy transfer
Show the answer

Answer: B At right angles to the direction of energy transfer

In a transverse wave the particles (or fields) oscillate at right angles (perpendicular) to the direction the wave carries energy. Ripples on water and all electromagnetic waves are transverse.

Checked against AQA GCSE Physics 8463 specification, 4.6.1.1 and 4.6.1.2 Transverse and longitudinal waves, properties of waves

08 / Waves in matterBoth tiers

In a longitudinal wave, how are the oscillations arranged?

  1. AAt 45° to the direction of energy transfer
  2. BAt right angles to the direction of energy transfer
  3. CIn random directions that keep changing
  4. DParallel to the direction of energy transfer
Show the answer

Answer: D Parallel to the direction of energy transfer

In a longitudinal wave the particles oscillate back and forth along the same line that the energy travels. This makes compressions, where particles are squashed together, and rarefactions, where they are spread out.

Checked against AQA GCSE Physics 8463 specification, 4.6.1.1 and 4.6.1.2 Transverse and longitudinal waves, properties of waves

09 / Waves in matterBoth tiers

Which of these is a longitudinal wave?

  1. ALight from the Sun
  2. BSound travelling through air
  3. CRadio waves from a mast
  4. DRipples on a pond
Show the answer

Answer: B Sound travelling through air

Sound waves in air are longitudinal: the air particles move back and forth along the direction of travel. Ripples on water and all electromagnetic waves (light, radio waves, microwaves) are transverse.

Checked against AQA GCSE Physics 8463 specification, 4.6.1.1 and 4.6.1.2 Transverse and longitudinal waves, properties of waves

10 / Waves in matterBoth tiers

A cork floats on a pond as ripples pass it. What does the cork do?

  1. ABobs up and down in about the same place
  2. BMoves along with the ripples to the edge
  3. CSinks to the bottom of the pond
  4. DMoves towards the source of the ripples
Show the answer

Answer: A Bobs up and down in about the same place

Waves carry energy (and information) without carrying the material along. A floating cork just bobs up and down as ripples pass, and the air near a loudspeaker vibrates but does not blow away. The wave travels, not the water or air.

Checked against AQA GCSE Physics 8463 specification, 4.6.1.1 and 4.6.1.2 Transverse and longitudinal waves, properties of waves

11 / Waves in matterBoth tiers

To find the frequency of ripples in a ripple tank, you can:

  1. AMeasure the distance between two peaks
  2. BMeasure the height of a ripple with a ruler
  3. CTime one ripple crossing the whole tank
  4. DCount the waves passing a point in 10 s and divide by 10
Show the answer

Answer: D Count the waves passing a point in 10 s and divide by 10

In a ripple tank, count the waves passing a point in a set time to find the frequency, and measure across several waves on the shadow to find one wavelength. Then wave speed = frequency × wavelength.

Checked against AQA GCSE Physics 8463 specification, 4.6.1.1 and 4.6.1.2 Transverse and longitudinal waves, properties of waves

12 / Waves in matterBoth tiers

Two pupils stand far apart. One bangs two blocks together and the other times from seeing the bang to hearing it. What else must they measure to find the speed of sound?

  1. AThe frequency of the sound
  2. BThe mass of the blocks
  3. CThe loudness of the bang
  4. DThe distance between them
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Answer: D The distance between them

Speed = distance ÷ time. Light arrives almost at once, so the time from seeing a bang to hearing it is the time the sound takes. For an echo, the sound goes to the wall and back, so it travels twice the distance to the wall.

Checked against AQA GCSE Physics 8463 specification, 4.6.1.1 and 4.6.1.2 Transverse and longitudinal waves, properties of waves

13 / Waves in matterBoth tiers · separate only

A wave reaches a boundary and bounces back. What is this called?

  1. ATransmission
  2. BReflection
  3. CAbsorption
  4. DRefraction
Show the answer

Answer: B Reflection

When a wave meets a boundary between two materials it can be reflected (bounce back), transmitted (pass through) or absorbed (its energy is taken in by the material). Often all three happen, in different amounts.

Checked against AQA GCSE Physics 8463 specification, 4.6.1.3 Reflection of waves

14 / Waves in matterBoth tiers · separate only

What is an echo?

  1. AAn absorbed sound wave
  2. BA reflected sound wave
  3. CA sound wave that has sped up
  4. DA transmitted sound wave
Show the answer

Answer: B A reflected sound wave

An echo is sound that has been reflected from a surface such as a wall or cliff. Hard, smooth surfaces reflect sound well; soft materials such as curtains absorb more of it.

Checked against AQA GCSE Physics 8463 specification, 4.6.1.3 Reflection of waves

15 / Waves in matterBoth tiers · separate only

Sound passes from air into water. Which of these stays the same?

  1. AIts speed and its wavelength
  2. BIts speed
  3. CIts frequency
  4. DIts wavelength
Show the answer

Answer: C Its frequency

The frequency is set by the source, so it does not change when a wave enters a new material. The speed changes, so the wavelength changes too (v = f λ): sound speeds up in water, so its wavelength gets longer.

Checked against AQA GCSE Physics 8463 specification, 4.6.1.2 Properties of waves (sound passing from one medium to another)

16 / Waves in matterHigher only · separate only

Which part of the ear first turns sound waves in air into vibrations of a solid?

  1. AThe nerve to the brain
  2. BThe cochlea
  3. CThe eardrum
  4. DThe ear canal
Show the answer

Answer: C The eardrum

Sound waves in the air make the eardrum vibrate. The eardrum passes the vibrations to tiny bones and on to the inner ear, which sends signals to the brain. So sound in air is turned into vibrations in solids.

Checked against AQA GCSE Physics 8463 specification, 4.6.1.4 Sound waves (physics only, HT)

17 / Waves in matterHigher only · separate only

Why can humans hear only a limited range of frequencies?

  1. AVery high frequency sound cannot travel through air
  2. BParts of the ear only vibrate well over a limited range
  3. CHigh frequency sound travels too fast to hear
  4. DVery low frequency sound carries no energy
Show the answer

Answer: B Parts of the ear only vibrate well over a limited range

Hearing depends on sound making the eardrum and the small bones vibrate. These parts only respond well over a limited range of frequencies, so sounds that are too high or too low are not heard, even though they travel through the air.

Checked against AQA GCSE Physics 8463 specification, 4.6.1.4 Sound waves (physics only, HT)

18 / Waves in matterHigher only · separate only

What is ultrasound?

  1. AA very loud sound
  2. BSound too low in frequency for humans to hear
  3. CAn electromagnetic wave
  4. DSound too high in frequency for humans to hear
Show the answer

Answer: D Sound too high in frequency for humans to hear

Ultrasound is sound above the range of human hearing. When it meets a boundary between two different tissues, part of it is reflected. The time each echo takes to return shows how deep that boundary is, and a computer builds an image.

Checked against AQA GCSE Physics 8463 specification, 4.6.1.5 Waves for detection and exploration (physics only, HT)

19 / Waves in matterHigher only · separate only

Why is ultrasound, not X-rays, used to scan an unborn baby?

  1. AUltrasound is an electromagnetic wave
  2. BUltrasound travels faster than X-rays
  3. CUltrasound is not ionising
  4. DX-rays cannot pass through skin
Show the answer

Answer: C Ultrasound is not ionising

X-rays are ionising and can damage cells, which matters most for a growing baby. Ultrasound is sound, not electromagnetic radiation, and is not ionising, so it is used for scans in pregnancy.

Checked against AQA GCSE Physics 8463 specification, 4.6.1.5 Waves for detection and exploration (physics only, HT)

20 / Waves in matterHigher only · separate only

A ship sends a sound pulse down and times its echo from the sea bed. Why is the time halved to find the depth?

  1. AThe pulse travels down and back up again
  2. BSound slows down in deep water
  3. CThe echo is only half as loud
  4. DHalf of the pulse is absorbed
Show the answer

Answer: A The pulse travels down and back up again

Echo sounding sends high frequency sound pulses through water and times the echoes. The sound goes to the sea bed (or a shoal of fish, or a wreck) and back, so depth = speed × time ÷ 2.

Checked against AQA GCSE Physics 8463 specification, 4.6.1.5 Waves for detection and exploration (physics only, HT)

21 / Waves in matterHigher only · separate only

Nobody can drill to the Earth’s core. How have scientists learned about it?

  1. ABy lowering cameras down deep mines
  2. BBy measuring light given off by the core
  3. CBy taking X-ray images of the Earth
  4. DBy studying how earthquake waves travel through the Earth
Show the answer

Answer: D By studying how earthquake waves travel through the Earth

Earthquakes send seismic waves through the whole Earth. Their speed and direction change in different layers, and some kinds cannot pass through liquid, so where the waves arrive, and when, reveals the hidden structure inside.

Checked against AQA GCSE Physics 8463 specification, 4.6.1.5 Waves for detection and exploration (physics only, HT)

02 / Longer answersMarked by levels

6-mark questions on this topic

Write your answer first, on paper. Then open it and tick off the points you made. How 6-mark questions are marked.

6 marks / Transverse and longitudinal wavesBoth tiers

Compare transverse and longitudinal waves, using ripples on water and sound in air as examples, and describe evidence that it is the wave and not the water or air that travels.

What a full answer includes
  • Both kinds of wave transfer energy from one place to another without transferring matter.
  • In a transverse wave the vibrations are at right angles to the direction in which the wave travels.
  • In a longitudinal wave the vibrations are parallel to the direction in which the wave travels.
  • Ripples on water are transverse waves and sound waves in air are longitudinal waves.
  • A transverse wave has peaks and troughs, while a longitudinal wave has compressions and rarefactions.
  • A cork floating on ripples bobs up and down in the same place and is not carried along with the waves.
  • In a sound wave the air particles only vibrate backwards and forwards about the same positions; a candle flame in front of a loudspeaker flickers but is not blown away.

Model answer

Transverse and longitudinal waves both transfer energy from one place to another without transferring matter. The difference is the direction of the vibrations. In a transverse wave, such as a ripple on water, the vibrations are at right angles to the direction in which the wave travels, so the water surface moves up and down as the wave moves across it, making peaks and troughs. In a longitudinal wave, such as a sound wave in air, the vibrations are parallel to the direction in which the wave travels, so the air particles move backwards and forwards along the line of the wave, making compressions where they are squashed together and rarefactions where they are spread apart. There is evidence that the wave travels but the medium does not. A cork floating on ripples bobs up and down in the same place and is not carried along with the waves. For sound, a candle flame placed in front of a loudspeaker flickers backwards and forwards but is not blown away, showing that the air only vibrates about the same position while the sound travels on.

Where marks slip

The two directions are often mixed up. In a transverse wave the vibrations are at right angles to the direction of travel; in a longitudinal wave they are along it. A floating object moves up and down, not along with the wave.

6 marks / Seismic waves and the Earth’s coreHigher only · separate only

Earthquakes produce two kinds of seismic wave. P-waves are longitudinal and S-waves are transverse. Detectors all over the world record which waves arrive and when. On the side of the Earth opposite an earthquake there is a large region where no S-waves are detected, and there are also regions where almost no P-waves arrive.

Explain how these observations give evidence about the structure of the Earth’s core.

What a full answer includes
  • Seismic waves travel through the Earth from the earthquake to detectors around the world.
  • S-waves are transverse and cannot travel through a liquid.
  • No S-waves are detected over a large region opposite the earthquake, so part of the core must be liquid.
  • P-waves are longitudinal and can travel through both solids and liquids.
  • The speed of the waves changes as they pass through layers of different density, so their paths curve, and they change direction sharply where they cross a boundary between layers.
  • P-waves are refracted where they enter and leave the core, which leaves regions on the surface where almost no P-waves arrive.
  • The sizes and positions of these regions let scientists work out the size of the core.
  • The core cannot be seen or reached, so this indirect evidence from waves is how its structure was discovered.

Model answer

When an earthquake happens, P-waves and S-waves travel through the Earth to detectors all around the world. S-waves are transverse and cannot travel through a liquid. No S-waves are detected over a large region on the opposite side of the Earth, which shows that they cannot pass through the core, so at least part of the core must be liquid. P-waves are longitudinal and can travel through both solids and liquids, so they can pass through the core. However, the speed of seismic waves changes as they travel through materials of different density, so their paths curve gently inside the Earth and they change direction sharply, by refraction, where they cross the boundary into or out of the core. This refraction of P-waves at the core leaves regions on the surface where almost no P-waves arrive. By measuring where these regions are and how big they are, scientists can work out the size of the core. Nobody can see or drill down to the core, so this indirect evidence from seismic waves is how its structure was discovered.

Where marks slip

Answers often say the waves “avoid” the core or bounce off it. Say that S-waves cannot travel through liquid and that P-waves refract because their speed changes when they enter a different material.

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