IGCSE Physics 3.1 General Wave Properties MCQs – 30 Practice Questions with Answers (Cambridge 0625)
Free practice MCQs for Cambridge IGCSE Physics (0625) Section 3.1, General Wave Properties, covering both Core and Supplement material. Work through each question, then open the Show Answer toggle to check the fully worked explanation.
Formula recap: v = f × λ | T = 1 ÷ f | frequency is measured in hertz (Hz), wavelength in metres (m), speed in m/s. Need the full revision sheet? See the IGCSE Physics Formula Sheet.
Wave Basics & the Wave Equation
Q1. What is the frequency of a wave?
- (A) The distance between two neighbouring crests
- (B) The number of complete waves passing a point in one second
- (C) The maximum displacement of a point from its rest position
- (D) The time taken for one complete wave to pass a point
Show Answer
Answer: B – Frequency is the number of complete waves (oscillations) passing a fixed point per second, measured in hertz (Hz). Option A is the wavelength, C is the amplitude, and D is the period.
Q2. A water wave has a frequency of 5.0 Hz and a wavelength of 2.0 m. What is the speed of the wave?
- (A) 0.40 m/s
- (B) 2.5 m/s
- (C) 10 m/s
- (D) 25 m/s
Show Answer
Answer: C – Use v = f × λ = 5.0 × 2.0 = 10 m/s.
Q3. A wave has a frequency of 4.0 Hz. What is its period?
- (A) 0.25 s
- (B) 0.40 s
- (C) 2.5 s
- (D) 4.0 s
Show Answer
Answer: A – Period T = 1 ÷ f = 1 ÷ 4.0 = 0.25 s. The period is the time for one complete wave.
Q4. A diagram shows 4 complete waves fitting exactly along a distance of 2.0 m. What is the wavelength of the waves?
- (A) 0.25 m
- (B) 2.0 m
- (C) 8.0 m
- (D) 0.50 m
Show Answer
Answer: D – Wavelength λ = total distance ÷ number of waves = 2.0 ÷ 4 = 0.50 m.
Q5. The amplitude of a wave is best described as…
- (A) the distance from one crest to the next crest
- (B) the maximum displacement of a point on the wave from its undisturbed (rest) position
- (C) the number of waves produced each second
- (D) the distance the wave travels in one second
Show Answer
Answer: B – Amplitude is the maximum displacement from the rest position, e.g. from the centre line to a crest. It is not measured from trough to crest (that would be twice the amplitude).
Q6. Ripples on water have a wavelength of 20 cm and a frequency of 15 Hz. What is the speed of the ripples?
- (A) 3.0 m/s
- (B) 300 m/s
- (C) 0.75 m/s
- (D) 1.3 m/s
Show Answer
Answer: A – First convert the wavelength: 20 cm = 0.20 m. Then v = f × λ = 15 × 0.20 = 3.0 m/s. Forgetting to convert cm to m gives the trap answer 300 m/s.
Q7. A student counts 30 wave crests passing a post in 10 s. What is the frequency of the waves?
- (A) 0.33 Hz
- (B) 300 Hz
- (C) 3.0 Hz
- (D) 30 Hz
Show Answer
Answer: C – Frequency = number of waves ÷ time = 30 ÷ 10 = 3.0 Hz.
Q8. On a transverse wave, the distance between two neighbouring crests is equal to…
- (A) the amplitude
- (B) half the amplitude
- (C) twice the wavelength
- (D) one wavelength
Show Answer
Answer: D – The wavelength is the distance between two adjacent points oscillating in phase, such as crest to crest or trough to trough.
Q9. A radio wave has a frequency of 2.5 kHz and a wavelength of 0.12 m. What is its speed?
- (A) 0.30 m/s
- (B) 30 m/s
- (C) 21 m/s
- (D) 300 m/s
Show Answer
Answer: D – Convert first: 2.5 kHz = 2500 Hz. Then v = f × λ = 2500 × 0.12 = 300 m/s.
Q10. Sound waves travel at 340 m/s in air. A sound has a frequency of 170 Hz. What is its wavelength?
- (A) 2.0 m
- (B) 0.50 m
- (C) 170 m
- (D) 57 800 m
Show Answer
Answer: A – Rearrange v = f × λ to get λ = v ÷ f = 340 ÷ 170 = 2.0 m.
Transverse vs Longitudinal Waves
Q11. In a transverse wave, the vibrations of the particles are…
- (A) parallel to the direction of energy transfer
- (B) in circles around the direction of travel
- (C) at right angles (perpendicular) to the direction of energy transfer
- (D) in the same direction as the wave at all times and places
Show Answer
Answer: C – In a transverse wave the oscillations are perpendicular to the direction in which the wave (and its energy) travels. Examples are water waves and all electromagnetic waves, including light.
Q12. Which wave is a longitudinal wave?
- (A) Light
- (B) Sound
- (C) Water waves on the surface of a pond
- (D) Waves on a stretched rope
Show Answer
Answer: B – Sound travels as a longitudinal wave: the air particles vibrate back and forth parallel to the direction of travel. Light, water surface waves and rope waves are transverse.
Q13. In a longitudinal wave, a compression is a region where…
- (A) the particles are closest together and the pressure is highest
- (B) the particles are furthest apart and the pressure is lowest
- (C) the particles have their maximum displacement from rest
- (D) the particles do not move at all
Show Answer
Answer: A – A compression is where the particles are pushed closest together, giving the highest pressure. The opposite region, where particles are spread out, is a rarefaction.
Q14. A rarefaction in a sound wave is a region where…
- (A) the air particles are squeezed closest together
- (B) the wave reflects from a surface
- (C) the amplitude of the wave is greatest
- (D) the air particles are spread furthest apart and the pressure is lowest
Show Answer
Answer: D – In a rarefaction the particles are spread out, so the pressure is at its lowest. Sound consists of a repeating pattern of compressions and rarefactions.
Q15. When a water wave travels across a pond, a floating cork bobs up and down but does not travel across with the wave. This shows that waves transfer…
- (A) both energy and matter across the pond
- (B) energy, without transferring matter overall
- (C) matter, without transferring energy
- (D) neither energy nor matter
Show Answer
Answer: B – Waves carry energy from place to place. The water (the medium) only oscillates about a fixed position and is not carried along with the wave.
Q16. On a wavefront diagram for water waves viewed from above, the distance between two neighbouring wavefront lines is…
- (A) the amplitude of the wave
- (B) the period of the wave
- (C) one wavelength
- (D) the speed of the wave
Show Answer
Answer: C – Wavefronts are lines joining points at the same stage of oscillation (e.g. all the crests). Neighbouring wavefronts are exactly one wavelength apart.
Q17. Which of these is a transverse wave?
- (A) Light from a torch
- (B) Sound from a loudspeaker
- (C) A wave travelling along a slinky spring when it is pushed and pulled
- (D) An ultrasound wave in air
Show Answer
Answer: A – Light is an electromagnetic wave and is transverse: its oscillations are at right angles to the direction of travel. Sound and ultrasound are longitudinal, as is the push-pull wave on a slinky.
Q18. A long spring (slinky) is given a quick push and pull at one end, along its own length. The wave produced is…
- (A) transverse, because the spring moves sideways
- (B) standing, because the spring does not move
- (C) electromagnetic, because energy is transferred
- (D) longitudinal, because the coils vibrate parallel to the direction of travel
Show Answer
Answer: D – Pushing and pulling along the spring makes the coils vibrate parallel to the direction the wave travels, producing compressions and rarefactions – a longitudinal wave.
Q19. In a ripple tank, a vibrating dipper touches the water surface 12 times each second. What is the frequency of the water waves produced?
- (A) 0.083 Hz
- (B) 12 Hz
- (C) 24 Hz
- (D) It cannot be found without knowing the wavelength
Show Answer
Answer: B – Each dip of the dipper produces one wave, so the wave frequency equals the frequency of the source: 12 Hz.
Q20. A small dot is painted on a rope through which a transverse wave is travelling. The dot moves…
- (A) up and down, staying at the same position along the rope
- (B) along the rope in the direction of the wave
- (C) in a complete circle
- (D) along the rope, opposite to the direction of the wave
Show Answer
Answer: A – Each part of the rope only oscillates up and down about its rest position. It is the wave pattern (and the energy) that travels along the rope, not the material of the rope.
Reflection, Refraction & Diffraction (wave behaviour)
Q21. A straight water wave strikes a straight barrier in a ripple tank at an angle of 35 degrees to the normal. At what angle to the normal is it reflected?
- (A) 0 degrees
- (B) 55 degrees
- (C) 70 degrees
- (D) 35 degrees
Show Answer
Answer: D – For reflection, the angle of incidence equals the angle of reflection, both measured from the normal (the line at right angles to the barrier). So the reflected wave also makes 35 degrees with the normal.
Q22. When plane water waves are reflected from a flat barrier, which quantities stay the same?
- (A) Only the direction of travel
- (B) Speed, frequency and wavelength
- (C) Only the amplitude
- (D) Speed and wavelength change, but frequency stays the same
Show Answer
Answer: B – Reflection changes only the direction of the waves. Because the waves stay in the same depth of water, their speed, frequency and wavelength are all unchanged.
Q23. When a wave crosses a boundary into a region where it travels more slowly (refraction), which quantity does NOT change?
- (A) Speed
- (B) Wavelength
- (C) Frequency
- (D) Direction must always change
Show Answer
Answer: C – The frequency is fixed by the source and never changes at a boundary. If the speed falls, the wavelength falls with it, because v = f × λ and f is constant.
Q24. Water waves travel from deep water into shallow water, where they move more slowly. What happens to their wavelength and frequency?
- (A) Wavelength decreases, frequency stays the same
- (B) Wavelength increases, frequency stays the same
- (C) Wavelength decreases, frequency increases
- (D) Wavelength stays the same, frequency decreases
Show Answer
Answer: A – Frequency is set by the source and cannot change. Since v falls and v = f × λ, the wavelength must decrease – the wavefronts get closer together in shallow water.
Q25. [Supplement] Water waves approach a boundary with shallow water at an angle, and slow down as they cross it. The waves bend…
- (A) away from the normal, because they speed up
- (B) away from the normal, because they slow down
- (C) towards the normal, because they slow down
- (D) towards the normal, because their frequency increases
Show Answer
Answer: C – When waves slow down on entering a new region, they bend towards the normal. If they speed up, they bend away from the normal. The frequency never changes.
Q26. Diffraction of water waves through a gap in a barrier is greatest (the waves spread out most) when…
- (A) the gap is very much wider than the wavelength
- (B) the width of the gap is about equal to the wavelength
- (C) the gap is very much narrower than the wavelength and blocks the waves completely
- (D) the waves have a very high frequency
Show Answer
Answer: B – Diffraction is most noticeable when the gap width is similar to (comparable with) the wavelength. With a very wide gap, only the edges of the wave spread slightly.
Q27. Waves in the open sea pass through a narrow harbour entrance and spread out to reach boats anchored in sheltered water behind the harbour wall. This spreading is an example of…
- (A) reflection
- (B) refraction
- (C) dispersion
- (D) diffraction
Show Answer
Answer: D – The waves spread out after passing through the narrow gap – this is diffraction. The narrower the gap compared with the wavelength, the more the waves spread.
Q28. [Supplement] A wave of frequency 8.0 Hz and wavelength 0.60 m crosses into a region where its speed is half its original value. What is its new wavelength?
- (A) 0.30 m
- (B) 0.60 m
- (C) 1.2 m
- (D) 4.8 m
Show Answer
Answer: A – The frequency stays at 8.0 Hz. Original speed v = f × λ = 8.0 × 0.60 = 4.8 m/s. New speed = 2.4 m/s, so new wavelength = v ÷ f = 2.4 ÷ 8.0 = 0.30 m. Halving the speed (at constant frequency) halves the wavelength.
Q29. Long-wavelength radio waves can be received in places that are hidden behind hills, but short-wavelength signals cannot. This is because long wavelengths…
- (A) travel much faster than short wavelengths
- (B) are reflected by the hills
- (C) diffract more around the hills
- (D) have a much higher frequency
Show Answer
Answer: C – Diffraction effects are stronger when the wavelength is large compared with the size of the obstacle or gap. Long radio waves bend around hills; short wavelengths travel in nearly straight lines and are blocked.
Q30. Waves approaching a coastline at an angle gradually turn so that they arrive almost parallel to the shore. This happens because…
- (A) the waves are reflected by the beach
- (B) the part of each wavefront reaching shallow water first slows down, bending the wavefront (refraction)
- (C) the frequency of the waves increases near the shore
- (D) diffraction spreads the waves out along the beach
Show Answer
Answer: B – Water becomes shallower near the shore, so the end of the wavefront that reaches shallow water first slows down while the other end continues faster. The wavefront swings round – refraction – until it is nearly parallel to the shoreline.
Keep practising: Explore more free MCQs for every board on our Physics MCQs hub, and keep the IGCSE Physics Formula Sheet open while you revise – the wave equation and T = 1 ÷ f appear again and again in Paper 2.
All questions on this page are original practice questions written for QuaidianPoint. They are not Cambridge past-paper questions.