IGCSE Physics 0625/22 May/June 2025 Past Paper with Answers

Question 1

Which instrument is most suitable for finding the volume of a small, irregularly shaped stone?

1. a measuring cylinder
2. a 30 cm ruler
3. a digital timer
4. a tape measure

Question 2

A steel ball is dropped and falls freely with no air resistance. Which statement describes its motion?

1. It falls with constant acceleration
2. It falls with constant speed
3. It falls with decreasing speed
4. It falls with increasing acceleration

Question 3

An object accelerates uniformly. Its velocity increases from 20 m/s to 100 m/s in a time of 40 s. What is its acceleration?

1. 2.0 m/s squared
2. 80 m/s squared
3. 0.50 m/s squared
4. 120 m/s squared

Question 4 · Answer A

Squashing the foam only reduces its volume; no matter is added or removed, so the amount of material is the same. The mass therefore stays the same, and since weight = mass times gravitational field strength, the weight is unchanged too.

Question 5 · Answer A

Density = mass divided by volume. The mass is found with a balance. Because the block is a regular rectangular shape, its volume is found by measuring its length, width and height with a ruler and multiplying them.

Question 6 · Answer A

The spring force at release = spring constant times extension = 30 x 0.12 = 3.6 N upward. The weight = mass times g = 0.15 x 9.8 = 1.47 N downward. The resultant upward force = 3.6 - 1.47 = 2.13 N. The acceleration = resultant force divided by mass = 2.13 / 0.15 = about 14 m/s squared.

Question 7 · Answer A

The velocity reverses, so the change of momentum = m(v - (-v)) = 0.15 x (30 - (-30)) = 0.15 x 60 = 9.0 kg m/s. The average force = change of momentum divided by contact time = 9.0 / (1.0 x 10^-3) = 9000 N.

Question 8 · Answer A

Setting kinetic energy equal to gravitational potential energy: half times m times v squared = m times g times h. The mass cancels, giving h = v squared divided by (2 times g). Substituting the speed, h = 5.0 squared / (2 x 9.8).

Question 9 · Answer A

Wind is caused by the Sun heating the atmosphere unevenly, so wind energy comes from the Sun. Geothermal energy comes from heat inside the Earth, and nuclear fuel energy comes from the nuclei of atoms, so neither of these comes from the Sun.

Question 10 · Answer A

A solid keeps its own fixed shape. Liquids and gases can flow and take the shape of their container. So a sample that takes the shape of its container must be either a liquid or a gas.

Question 11 · Answer A

In the collision the fast molecule transfers some momentum to the smoke particle, so the smoke particle starts to move. The light molecule bounces off (rebounds) with a changed direction. This is the basis of Brownian motion.

Question 12 · Answer A

At constant temperature, pressure multiplied by volume is constant: p1 V1 = p2 V2. So 360 x 2.0 = 120 x V2, giving 720 = 120 V2, so V2 = 720 / 120 = 6.0 cubic centimetres.

Question 13 · Answer A

Gases expand far more than solids or liquids for the same temperature rise. Warming the trapped air makes it expand much more than the glass or the mercury, so the expanding air pushes the mercury thread up the tube.

Question 14 · Answer A

The energy supplied by the heater is power multiplied by time, P times t. This equals m times c times theta. Rearranging for c gives c = P t divided by (m times theta).

Question 15 · Answer A

Thermal energy travels along each rod by conduction. The rod that conducts heat fastest reaches the wax soonest, melting it first. Since the silver ball falls first, silver must be the best thermal conductor of the four metals.

Question 16 · Answer A

Emission increases with a darker surface and a larger surface area. X is large and black, so it emits the most. Comparing the two white spheres, the large one Z emits more than the small one Y because it has a greater surface area. So the order is X, then Z, then Y.

Question 17 · Answer A

Wavelength = speed divided by frequency. "speed 350 m/s, frequency 280 Hz" gives 350 / 280 = 1.25 m. "speed 300 m/s, frequency 400 Hz" gives 300 / 400 = 0.75 m. "speed 300 m/s, frequency 280 Hz" gives 300 / 280 = 1.07 m. "speed 350 m/s, frequency 400 Hz" gives 350 / 400 = 0.88 m. The longest wavelength is 1.25 m, so the wave with speed 350 m/s and frequency 280 Hz diffracts the most.

Question 18 · Answer A

The amplitude of a wave is the maximum displacement of a point from its undisturbed (rest) position. It is measured from the middle line to a crest, or from the middle line to a trough.

Question 19 · Answer A

Seismic S-waves (secondary waves) are transverse waves. In a transverse wave the particles vibrate at right angles (perpendicular) to the direction in which the wave travels.

Question 20 · Answer A

A plane mirror forms a virtual image because the rays only appear to come from behind the mirror. The image is the same distance behind the mirror as the object is in front of it, and it is the same size as the object.

Question 21 · Answer A

Angles in the refractive index formula are measured from the normal, not from the boundary. The angle of incidence from the normal is 90 - 50 = 40 degrees and the angle of refraction from the normal is 90 - 64 = 26 degrees. So the refractive index is the sine of 40 degrees divided by the sine of 26 degrees.

Question 22 · Answer A

An enlarged, upright image on the same side as the object is a virtual image. A converging lens produces this only when the object is placed inside the focal length, that is closer to the lens than its principal focus.

Question 23 · Answer A

Light, like all electromagnetic waves, travels through air (and a vacuum) at approximately 3.0 x 10^8 metres per second. This is about 300 000 km/s.

Question 24 · Answer A

The pulse travels to the seabed and back, so the total distance is speed times time = 1500 x 4.6 = 6900 m. The depth is half of this because the pulse covers the depth twice: 6900 / 2 = 3450 m, which is about 3500 m.

Question 25 · Answer A

Both can hear a frequency only if it lies inside both ranges. The overlap starts at the higher lower-limit (150 Hz, set by the dolphin) and ends at the lower upper-limit (20 kHz, set by the human). So both can hear from 150 Hz to 20 kHz.

Question 26 · Answer A

The positive charge on the balloon attracts the free electrons in the wall towards the surface nearest the balloon. This leaves the wall surface negatively charged close to the balloon, so the opposite charges attract and the balloon sticks. This is charging by induction.

Question 27 · Answer A

An ammeter measures the current through the lamp, so it must be in series with the lamp. A voltmeter measures the potential difference across the lamp, so it must be connected in parallel with the lamp. The resistance is then voltage divided by current.

Question 28 · Answer A

Resistance is proportional to length, so a shorter wire has a smaller resistance. Resistance is inversely proportional to cross-sectional area, so a thinner wire (smaller diameter) has a greater resistance.

Question 29 · Answer A

In a series circuit the same current flows through both resistors, and the supply voltage is shared in proportion to the resistances. The fraction across R1 is R1 divided by the total resistance, so V1 = V multiplied by R1 divided by (R1 + R2).

Question 30 · Answer A

A diode only allows current to flow in one direction. When connected to an alternating supply it blocks the reverse half of each cycle, so the output current is in one direction only. This process is rectification, which converts a.c. to d.c.

Question 31 · Answer A

The two resistors are in parallel, so they have the same potential difference. Across the 4.0 ohm resistor this is V = I x R = 1.0 x 4.0 = 4.0 V. The current in the 2.0 ohm resistor is then I = V / R = 4.0 / 2.0 = 2.0 A. The total current from the cell is the sum of the branch currents: 1.0 + 2.0 = 3.0 A.

Question 32 · Answer A

The magnetic field around a straight wire forms concentric circles. Using the right-hand grip rule with the current pointing into the page, the field lines run clockwise when viewed from the front (looking in the direction of the current).

Question 33 · Answer A

For a 100% efficient transformer the input power equals the output power. The output power = secondary voltage times secondary current = 5.0 x 2.0 = 10 W. The input power = primary voltage times primary current = 3.0 x primary current. Setting these equal: primary current = 10 / 3.0 = about 3.3 A.

Question 34 · Answer A

Large-angle deflections happen when an alpha particle passes very close to a tiny, dense, positively charged nucleus and is strongly repelled. This shows that the positive charge and most of the mass of the atom are concentrated in a very small central nucleus.

Question 35 · Answer A

Some of the measured count rate is due to background radiation that is always present. The corrected count rate for the source is found by measuring the background count rate separately and subtracting it from the measured count rate.

Question 36 · Answer A

Beta particles are far less massive than alpha particles, so for a given field they are deflected much more than alpha particles. The statement that alpha particles are deflected the most is therefore incorrect. The other three statements are all correct.

Question 37 · Answer A

60 minutes is 60 divided by 20 = 3 half-lives. After each half-life the amount remaining halves: 1 then one half then one quarter then one eighth. So after 3 half-lives one eighth of the original sample remains.

Question 38 · Answer A

The Moon takes about one month to complete one orbit of the Earth. The Earth orbits the Sun once per year (about 365 days) and rotates once every 24 hours; the Sun does not orbit the Earth.

Question 39 · Answer A

A stable star is powered by nuclear fusion, in which hydrogen nuclei join together to form helium, releasing a very large amount of energy. This outward energy flow balances the inward pull of gravity.

Question 40 · Answer A

First convert the speed: 3000 km/s = 3.0 x 10^6 m/s. The distance = speed divided by the Hubble constant = (3.0 x 10^6) / (2.2 x 10^-18) = about 1.4 x 10^24 m.