IGCSE Physics 0625/11 May/June 2025 Past Paper with Answers

Question 1

A measuring cylinder has scale divisions every $2.0\ \text{cm}^3$. The liquid surface sits exactly halfway between the marks labelled $14\ \text{cm}^3$ and $18\ \text{cm}^3$. What is the volume of the liquid?

1. $16.0\ \text{cm}^3$
2. $13.0\ \text{cm}^3$
3. $13.5\ \text{cm}^3$
4. $17.0\ \text{cm}^3$

Question 2

Which statement about the speed and velocity of an object is correct?

1. Velocity is the speed of an object in a stated direction.
2. Speed is always greater than velocity.
3. Speed and velocity are always positive.
4. Speed is in m/s but velocity is in km/h.

Question 3

A runner records these times in three races. Race 1: $100\ \text{m}$ in $12\ \text{s}$. Race 2: $150\ \text{m}$ in $17\ \text{s}$. Race 3: $200\ \text{m}$ in $25\ \text{s}$. What is the order of the runner's average speeds in each race, from lowest to highest?

1. 3, 1, 2
2. 1, 2, 3
3. 2, 1, 3
4. 3, 2, 1

Question 4 · Answer A

Step 1: Weight = mass $\times$ gravitational field strength, so $W = mg$. Step 2: Substitute: $W = 2.00 \times 9.8 = 19.6\ \text{N}$.

Question 5 · Answer A

Step 1: An object floats if its density is less than the liquid's density. Step 2: Density = mass / volume. W: $2.0/3.0 \approx 0.67\ \text{g/cm}^3$. X: $1.0/0.5 = 2.0\ \text{g/cm}^3$. Y: $6.0/4.0 = 1.5\ \text{g/cm}^3$. Z: $9.0/6.0 = 1.5\ \text{g/cm}^3$. Step 3: Only W has a density below $1.4\ \text{g/cm}^3$, so only W floats.

Question 6 · Answer A

Step 1: As the car speeds up, the resistive forces grow because they are proportional to the speed. Step 2: The driving force is constant, so the resultant force shrinks. Step 3: When the resistive forces equal the driving force, the resultant is zero. Step 4: Zero resultant means zero acceleration, so the speed stays at its maximum value.

Question 7 · Answer A

Step 1: Springs that are squashed or stretched gain elastic potential energy. Step 2: The mattress springs are compressed by the person's weight, so the energy stored elastically in the springs increases.

Question 8 · Answer A

Step 1: Biofuel, coal and oil release energy by burning - their store is chemical energy in molecular bonds. Step 2: Nuclear fuel releases energy from the nucleus of the atom (fission), not from chemical bonds. Step 3: So nuclear fuel does not have a chemical energy store.

Question 9 · Answer A

Step 1: Total mass = $20 \times 1.2 = 24\ \text{kg}$. Step 2: Total weight = $24 \times 9.8 = 235.2\ \text{N}$. Step 3: Work done against gravity = force $\times$ height = $235.2 \times 15 = 3528\ \text{J} \approx 3500\ \text{J}$.

Question 10 · Answer A

Step 1: Pressure = force / area. Step 2: A larger force (weight) and a smaller area both increase pressure. Step 3: Therefore the change that always increases pressure is to increase the weight while decreasing the contact area.

Question 11 · Answer A

Step 1: A pure substance melts at a fixed temperature, shown by a flat region on a heating curve. Step 2: Y's plateau is at $50\ ^\circ\text{C}$ and X's plateau is at $80\ ^\circ\text{C}$. Step 3: Since the plateaus are the melting points, Y has the lower melting point.

Question 12 · Answer A

Step 1: Both liquids and gases are fluids - their particles can move past each other, so both can flow. Step 2: Shape, volume and compressibility all change when a liquid becomes a gas: a gas fills its container and is much easier to compress. Step 3: The only property unchanged is the ability to flow.

Question 13 · Answer A

Step 1: Solids have tightly packed particles with almost no space between them, so a solid resists being squeezed smaller. Step 2: Gases have particles far apart with large gaps; the gaps can be reduced, so a gas is easily compressed. Step 3: The key difference is the spacing of the particles.

Question 14 · Answer A

Step 1: Pressure on the syringe wall comes from gas particles striking it. Step 2: When the volume is larger, the same particles are spread over more space, so each piece of wall is hit less often per second. Step 3: Fewer collisions per second means lower pressure.

Question 15 · Answer A

Step 1: Molecules in a liquid have a range of speeds and so a range of kinetic energies. Step 2: Only the molecules near the surface that have enough kinetic energy can break free from the attractive forces. Step 3: It is the most energetic molecules that escape, leaving the slower ones behind (so the remaining liquid cools).

Question 16 · Answer A

Step 1: A shorter time for the pin to fall means heat reached the cold end faster, so the material is a better thermal conductor. Step 2: X (30 s) takes less time than Y (80 s), so X is the better conductor of the two. Step 3: All other comparisons fail: Y, Z and Z again take longer than the rod they are compared with.

Question 17 · Answer A

Step 1: Dark, matt surfaces are the best emitters and absorbers of thermal radiation. Step 2: Shiny, light-coloured surfaces emit (and absorb) thermal radiation the worst. Step 3: Of the four options, dull black is the darkest and most matt, so it emits thermal radiation at the highest rate.

Question 18 · Answer A

Step 1: Frequency = number of waves / time = $4.0/10 = 0.40\ \text{Hz}$. Step 2: Wave equation: $v = f\lambda$, so $\lambda = v/f$. Step 3: $\lambda = 2.0 / 0.40 = 5.0\ \text{m}$.

Question 19 · Answer A

Step 1: In a transverse wave, the vibrations are perpendicular (at right angles) to the direction the wave travels. Step 2: Water waves are transverse: the surface moves up and down while the wave moves horizontally. Step 3: Sound waves are longitudinal, with vibrations parallel to the direction of travel.

Question 20 · Answer A

Step 1: A wavefront is a line joining points on a wave that are all at the same point in their cycle (for ripples, the curved crest line). Step 2: The wavelength is the perpendicular distance between two such wavefronts. Step 3: So X (the crest line) is a wavefront, and Y (gap between crests) is the wavelength.

Question 21 · Answer A

Step 1: A vertical mirror reflects left and right but not top and bottom. The number 12 stays at the top and 6 at the bottom; the 3 and 9 swap. Step 2: Hour: reflected hour 5 corresponds to actual hour $12 - 5 = 7$. Step 3: Minute: reflected 45 min (hand at 9) corresponds to actual $60 - 45 = 15$ min (hand at 3). Step 4: Actual time = $7{:}15$.

Question 22 · Answer A

Step 1: Angle of reflection equals angle of incidence, so it is also $40\ ^\circ$ to the normal. Step 2: Light slows down when entering glass from air, so it bends towards the normal. Step 3: That means the angle of refraction is smaller than the angle of incidence: less than $40\ ^\circ$.

Question 23 · Answer A

Step 1: Loudness depends on amplitude: larger amplitude means louder sound. Step 2: Pitch depends on frequency: higher frequency means higher pitch. Step 3: If both amplitude and frequency rise, loudness rises and pitch rises.

Question 24 · Answer A

Step 1: The human audible range is $20\ \text{Hz}$ to $20\,000\ \text{Hz}$. Step 2: Ultrasound has frequencies above $20\,000\ \text{Hz}$ but travels at the same speed as audible sound in air, about $330\ \text{m/s}$.

Question 25 · Answer A

Step 1: Soft iron is a soft magnetic material: it magnetises and demagnetises easily. Step 2: Steel is a hard magnetic material: once magnetised, it retains its magnetism (hard to demagnetise). Step 3: So soft iron is easy and steel is hard to demagnetise.

Question 26 · Answer A

Step 1: Unlike charges attract, like charges repel. Step 2: X is attracted by a negative rod, so X must be the opposite sign: positive. Step 3: Y is repelled by the negative rod, so Y must be the same sign: negative.

Question 27 · Answer A

Step 1: Power $P = V \times I$. Step 2: Car headlight: $12 \times 3.0 = 36\ \text{W}$. Cooling fan: $110 \times 0.40 = 44\ \text{W}$. Electric spark generator: $400\,000 \times 0.000\,1 = 40\ \text{W}$. Mains lamp: $240 \times 0.20 = 48\ \text{W}$. Step 3: The mains lamp has the largest power, $48\ \text{W}$.

Question 28 · Answer A

Step 1: A double-insulated appliance has the live parts insulated and is also surrounded by a second layer of insulation, often the outer plastic casing. Step 2: This means the casing cannot become live and the appliance does not need an earth wire. Step 3: Fuses and neutral connections are still required for normal operation.

Question 29 · Answer A

Step 1: A magnetic field is defined as a region in which a magnetic pole feels a force. Step 2: Most objects, most metals (such as copper or aluminium), and stationary charges do not feel this force, so only magnetic poles are the right test object.

Question 30 · Answer A

Step 1: Only electrons can move easily between materials when they are rubbed together; protons and neutrons stay locked in the nucleus. Step 2: Losing electrons leaves a net positive charge. Step 3: Therefore the plastic rod becomes positive because electrons have been transferred away from it.

Question 31 · Answer A

Step 1: Cells in series add their e.m.f.s, so total e.m.f. = $1.5 + 1.5 + 1.5 = 4.5\ \text{V}$. Step 2: Resistors in series add their resistances, so total resistance = $20 + 20 = 40\ \Omega$.

Question 32 · Answer A

Step 1: Force on each wire in the coil = $BIL$, so it grows with the current. Step 2: The turning effect also grows with the number of turns because more wires share the same force. Step 3: Increasing both the current and the number of turns must therefore increase the turning effect.

Question 33 · Answer A

Step 1: The size of the magnetic field around a straight wire grows with the size of the current. The current doubles from $3.0$ to $6.0\ \text{A}$, so the field strength rises. Step 2: Reversing the current direction reverses the direction in which the field lines circle the wire. Step 3: Combining both effects: stronger field, opposite direction.

Question 34 · Answer A

Step 1: All contributions to background radiation must add to $100\%$. Step 2: Sum of the four listed sources = $48 + 13 + 10 + 11 = 82\%$. Step 3: Remaining sources = $100 - 82 = 18\%$.

Question 35 · Answer A

Step 1: Alpha emission removes 2 protons (proton number drops by 2). Step 2: Beta-minus emission converts a neutron into a proton (proton number rises by 1). Step 3: Gamma emission carries away energy as electromagnetic radiation; the nucleus loses no protons or neutrons, so the proton number is unchanged.

Question 36 · Answer A

Step 1: A neutral atom contains equal numbers of protons and electrons. Step 2: Losing one or more electrons leaves the atom with more protons than electrons, so it becomes positive. Step 3: A charged atom is called an ion, so atoms become positively charged ions.

Question 37 · Answer A

Step 1: Atomic number Z = number of protons in the nucleus. Step 2: For this isotope, Z = 36, so the nucleus contains 36 protons. (Mass number $A = 78$ would give 78 minus 36 = 42 neutrons, which is not asked.)

Question 38 · Answer A

Step 1: A day, the time the Earth takes to spin once on its axis, is about $24$ hours. Step 2: A year, the time for one full orbit of the Sun, is about $365$ days. Step 3: So the correct pair is $24$ hours for the spin and $365$ days for the orbit.

Question 39 · Answer A

Step 1: Redshift means the observed wavelength is longer than the emitted wavelength. Step 2: Light from galaxies moving away from us is redshifted; light from those moving towards us is blueshifted. Step 3: The Big Bang theory says the whole Universe expanded from a very small point and has been expanding for about $14$ billion years.

Question 40 · Answer A

Step 1: The Milky Way is the galaxy that contains the Sun and roughly $100$ billion other stars. Step 2: It is not inside the Solar System - the Solar System is one tiny part of the Milky Way. Step 3: Some of the stars we can see in the sky are in the Milky Way, but the Milky Way as a whole is the galaxy itself, not just the stars we can see.