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Physics 0625 · for examination in 2026, 2027 and 2028

Topic 3 · Waves

General wave properties, reflection and refraction, thin lenses, dispersion, the electromagnetic spectrum, and sound.

Written in the format of: Papers 1 and 2 (multiple choice), Papers 3 and 4 (theory), Paper 6 (alternative to practical)

Written by GioPhysics from the published syllabus. These are practice papers in the style of Cambridge IGCSE Physics 0625; they are not Cambridge papers, contain no past-paper questions, and the official syllabus and specimen materials remain the authority. Cambridge IGCSE Physics 0625 syllabus

Marks
3813
Questions
106
Multiple choice
65
Suggested time
45 minutes
PDFPrint the paperThe paper with writing space, then the mark scheme as a second booklet. Free.PPTXTeach it from the boardOne slide per question with its figure, each followed by its mark scheme. Editable.

How hard the questions are

Pitched at the board's own level, not above it. Multiple choice is mostly one step, with a couple of two-step items and one that rewards the candidate who does not take the obvious route. Structured questions open on a 1-mark recall and close on an explanation or a suggestion worth two marks — the marks real candidates most often drop.

  • 33RecallOne idea, one step. The mark is for knowing it.
  • 43RoutineThe standard application — the named equation, the usual graph read.
  • 20DemandingSeveral steps, and you have to choose them. Nothing says which comes first.
  • 10DiscriminatingThe part that separates the top grade: an unfamiliar context, a derivation, or an argument that has to hold together to earn anything.
Multiple choiceRecallCore3.1[1]

Which statement describes a longitudinal wave?

  1. AThe particles vibrate at right angles to the direction of energy transfer.
  2. BThe particles vibrate along the direction of energy transfer.
  3. CThe particles travel with the wave from one place to another.
  4. DThe wave cannot travel through a solid.
Ready to self-mark?Reveal the detailed answerAO11 mark

Answer overview

BThe particles vibrate along the direction of energy transfer.

Multiple choiceRoutineCore3.1[1]

Water waves in a ripple tank have a wavelength of 2.5 cm. 12 complete waves pass a fixed point in 4.0 s. What is the speed of the waves?

Profile of the ripple-tank waves at one instant0246810distance / cm2.5 cmone wavelengthdirection of travel
Fig. 2.1 A snapshot of the water surface in the ripple tank at one instant, drawn as a side view. Four complete waves run left to right above a horizontal distance scale that is marked in centimetres from 0 to 10, the scale line itself being the undisturbed water level. A dimension line drawn between two neighbouring crests is labelled one wavelength, 2.5 cm, and a separate arrow above the wave shows the direction in which the waves are travelling.
  1. A0.83 cm/s
  2. B7.5 cm/s
  3. C30 cm/s
  4. D120 cm/s
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Answer overview

B7.5 cm/s

Multiple choiceRoutineSupp.3.2[1]

A ray of light travels from air into a transparent block of refractive index 1.5. The angle of incidence in air is 40°. What is the angle of refraction in the block? (sin 40° = 0.643)

  1. A17°
  2. B25°
  3. C40°
  4. D74°
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Answer overview

B25°

Multiple choiceRecallCore3.3[1]

Which list places these electromagnetic waves in order of increasing frequency?

  1. Ainfrared, microwaves, ultraviolet, X-rays
  2. Bmicrowaves, infrared, ultraviolet, X-rays
  3. CX-rays, ultraviolet, infrared, microwaves
  4. Dultraviolet, X-rays, microwaves, infrared
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Answer overview

Bmicrowaves, infrared, ultraviolet, X-rays

Multiple choiceRoutineCore3.4[1]

A student stands 165 m from a large wall and claps once. She hears the echo 1.0 s later. What is the speed of sound in air from her measurement?

A student standing in front of a large wallwallstudent165 m
Fig. 5.1 A side view of the arrangement. The student stands on level hatched ground on the left, facing a tall wall drawn as a hatched vertical slab standing on the same ground well to her right. A dimension line above her head runs horizontally from the student across to the face of the wall and is labelled 165 m. No sound path is drawn on the figure.
  1. A165 m/s
  2. B247 m/s
  3. C330 m/s
  4. D660 m/s
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Answer overview

C330 m/s

Multiple choiceRecallCore3.4[1]

In which material does sound travel fastest?

  1. Aair
  2. Ba vacuum
  3. Cwater
  4. Dsteel
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Answer overview

Dsteel

StructuredDemandingSupp.3.1[7]

Straight water waves in a ripple tank travel from a deep region into a shallow region. The boundary between the regions is a straight line, and the wavefronts meet it at 30° to the boundary. In the deep region the waves have a wavelength of 1.8 cm and a frequency of 8.0 Hz. In the shallow region the wavelength is 1.2 cm.

Straight water waves meeting the boundary of a shallow region30°boundarydeep watershallow water
Fig. 7.1 Plan view of the ripple tank, seen from above. A straight boundary runs right across the tank, dividing it into deep water in the upper part and shallow water in the lower part, each region labelled. Twelve straight parallel wavefronts, evenly spaced, fill the deep water and slope up to the right so that each one makes an angle of 30° with the boundary; that angle is marked with an arc where one front meets the boundary. The shallow region is drawn empty.
  1. (a)

    Calculate Calculate the speed of the waves in the deep region.

    [2]
    Ready to self-mark?Reveal the detailed answerAO22 marks

    Mark-by-mark answer

    1. v = fλ = 8.0 × 1.8

    2. v = 14.4 cm/s

  2. (b)

    Determine Determine the speed of the waves in the shallow region.

    [2]
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    Mark-by-mark answer

    1. the frequency is unchanged at 8.0 Hz as the waves cross the boundary

    2. v = 8.0 × 1.2 = 9.6 cm/s

  3. (c)

    Describe The wavefronts meet the boundary at an angle. Describe and explain what happens to the direction in which the waves travel as they cross into the shallow region.

    [3]
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    Mark-by-mark answer

    1. the direction of travel changes — the waves bend towards the normal to the boundary

    2. because the part of each wavefront that reaches the shallow water first slows down before the rest of it does

    3. so the wavefront pivots, and refraction has occurred

StructuredDiscriminatingSupp.3.2[9]

An optical fibre has a glass core of refractive index 1.50. Light entering one end of the fibre travels along it by repeated total internal reflection at the core boundary, even where the fibre is gently curved.

Light travelling along an optical fibre by total internal reflectionairairglass core, n = 1.50light innormal
Fig. 8.1 A straight length of optical fibre drawn in section as a long horizontal band with parallel walls, shaded to show glass and labelled glass core, n = 1.50, with air labelled outside it. Light entering the flat left-hand end travels up to the upper wall, reflects down to the lower wall, reflects again up to the upper wall and reaches the far end, giving a zig-zag path along the fibre. At one reflection a dashed normal is drawn perpendicular to the wall, and the angle on each side of it is marked with an arc; no angle is given a numerical value.
  1. (a)

    State State the two conditions necessary for total internal reflection to occur.

    [2]
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    Mark-by-mark answer

    1. the light must be travelling in the optically denser medium, towards a boundary with a less dense medium

    2. the angle of incidence at the boundary must be greater than the critical angle

  2. (b)

    Calculate Calculate the critical angle for the glass core.

    [3]
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    Mark-by-mark answer

    1. sin c = 1 / n

    2. sin c = 1 / 1.50 = 0.667

    3. c = 41.8° (accept 42°)

  3. (c)

    Explain A student suggests that bending the fibre very sharply would make no difference, because total internal reflection always happens. Explain why the student is wrong.

    [3]
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    Mark-by-mark answer

    1. bending the fibre sharply reduces the angle of incidence at the outer wall of the bend

    2. if that angle falls below the critical angle of 41.8°, the light is no longer totally internally reflected

    3. some light refracts out through the boundary and the signal is weakened or lost

  4. (d)

    Give Give one use of optical fibres other than in medicine.

    [1]
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    Mark-by-mark answer

    1. telephone / cable television / internet communication — any high-speed data transmission

StructuredRoutineCore3.3[8]

The electromagnetic spectrum is a family of transverse waves that all travel at the same speed in a vacuum, 3.0 × 10⁸ m/s.

  1. (a)

    State State one property, other than their speed in a vacuum, that all electromagnetic waves share.

    [1]
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    Mark-by-mark answer

    1. any one of: they are transverse; they transfer energy; they can travel through a vacuum; they can be reflected and refracted

  2. (b)

    Identify Identify the region of the electromagnetic spectrum used for each of the following, and give one different region for each: (i) cooking food in an oven that heats from the outside; (ii) sterilising medical equipment.

    [2]
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    Mark-by-mark answer

    1. For cooking food from the outside, the electromagnetic region is infrared radiation.

    2. (ii) gamma rays (accept ultraviolet for surface sterilisation)

  3. (c)

    Calculate A radio station broadcasts at a frequency of 95.8 MHz. Calculate the wavelength of the waves it emits.

    [3]
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    Mark-by-mark answer

    1. λ = v / f

    2. λ = 3.0 × 10⁸ / 95.8 × 10⁶

    3. λ = 3.1 m

  4. (d)

    Describe Describe one harmful effect of excessive exposure to ultraviolet radiation, and state one way of reducing the risk.

    [2]
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    Mark-by-mark answer

    1. damage to surface cells / skin ageing / skin cancer / eye damage such as cataracts

    2. wear sunscreen, sunglasses or protective clothing; limit exposure at midday

Practical skillsDemandingSupp.3.2[8]

A student determines the refractive index of a glass block using optical pins. She places the block on a sheet of paper, draws round it, and shines a ray at the top face at an angle of incidence i, marking the ray in and the ray out with pins. She repeats this for several values of i and measures the angle of refraction r inside the block.

A ray traced through a rectangular glass blockglass blocknormalincident rayiremergent ray
Fig. 10.1 The rectangular glass block drawn on the paper, seen from above. A ray labelled incident ray comes down from the upper left and meets the top face of the block; a dashed normal is drawn perpendicular to that face at the point where the ray strikes it. The angle between the incident ray and the normal is labelled i, and the angle between the normal and the ray travelling inside the glass is labelled r. The ray crosses the block, leaves through the bottom face and continues as the emergent ray. The optical pins are not shown.
The student's results
i / degrees2030405060
r / degrees13.219.525.430.735.3
sin i0.3420.5000.6430.7660.866
sin r0.2280.3340.4290.5110.578
  1. (a)

    Describe Describe how the student should place and use the optical pins so that the path of the ray is marked accurately.

    [3]
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    Mark-by-mark answer

    1. place two pins in the incident ray, as far apart as possible

    2. view from the far side of the block and place two more pins so that all four appear in line, one behind another

    3. remove the block and draw a straight line through each pair to find the ray in and the ray out

  2. (b)

    Explain Explain why plotting a graph of sin i against sin r gives a more reliable value for the refractive index than calculating sin i / sin r for a single pair of readings.

    [3]
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    Mark-by-mark answer

    1. n = sin i / sin r, so a graph of sin i against sin r should be a straight line through the origin of gradient n

    2. the gradient uses all of the readings rather than one, so random errors in individual measurements average out

    3. an anomalous result is visible as a point off the line and can be identified rather than silently included

  3. (c)

    Determine Use the first and last results to determine a value for the refractive index of the glass.

    [2]
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    Mark-by-mark answer

    1. gradient = (0.866 − 0.342) / (0.578 − 0.228) = 0.524 / 0.350

    2. n = 1.50 (accept 1.5)

The cheapest marks on any paper

What the command words are asking for

Every board publishes these and marks to them. A candidate who explains where the question said state has spent four minutes earning one mark; one who states where it said explain has earned none.

Calculate
Work out from given facts, figures or information.
Define
Give the precise meaning.
Describe
State the points of a topic; give characteristics and main features.
Determine
Establish an answer using the information available.
Estimate
Suggest an approximate value.
Explain
Set out purposes or reasons; make relationships evident; give why and/or how.
Give
Produce an answer from a given source or recall.
Identify
Name, select or recognise.
Show (that)
Provide structured evidence that leads to a given result.
State
Express in clear terms.
Suggest
Apply knowledge and understanding to situations where there is a range of valid responses in order to make proposals.

What is being tested

IGCSE assessment objectives, and how this paper divides between them

Every candidate sits two theory papers and one practical-skills paper. Core takes Papers 1 and 3 and is capped at grade C; Extended takes Papers 2 and 4 and reaches A*. Both then take either Paper 5 (practical test) or Paper 6 (alternative to practical), which carries 20% either way. Theory papers give you no formula sheet.

AO111 marks · 29%8 marks · 62%

Knowledge with understanding

Recall, describe, explain and use physics ideas, terminology, instruments and conventions.

Across the whole qualification: 50%

AO221 marks · 55%5 marks · 38%

Handling information and problem-solving

Locate and interpret information, translate between forms, calculate, reason, and apply physics to unfamiliar situations.

Across the whole qualification: 30%

AO36 marks · 16%0 marks · 0%

Experimental skills and investigations

Plan, use apparatus, record and present observations, analyse, evaluate, and suggest improvements.

Across the whole qualification: 20%