| Syllabus | Alternate Universe Cambridge 0625 |
| Subject | Physics (0625) Core |
| Paper | 0625/33/M/J/25 · Paper 3, Variant 3 |
| Also listed as | 0625_s25_qp_33 · 0625_s25_ms_33 |
| Session | May/June 2025 |
| Questions | 11, multiple choice, with answers and explanations |
| Cost | Free |
0625/33/M/J/25 answer key
Preview the first questions
Question 1
A racing car accelerates uniformly from $0\ \text{m/s}$ to $22\ \text{m/s}$ over a time of $4.0\ \text{s}$. What is the distance the car travels during this interval?
- $44\ \text{m}$
- $88\ \text{m}$
- $22\ \text{m}$
- $4.0\ \text{m}$
Show the answer and explanation
Correct answer: A
Step 1: The distance is the area under the speed-time line. For uniform acceleration from rest, this is a right-angled triangle. Step 2: Area $= \tfrac{1}{2} \times \text{base} \times \text{height} = \tfrac{1}{2} \times 4.0 \times 22 = 44\ \text{m}$.
Question 2
A heavy hammer has a weight of $25\,000\ \text{N}$ at the Earth's surface, where $g = 9.8\ \text{N/kg}$. What is the mass of the hammer?
- $2600\ \text{kg}$
- $245\,000\ \text{kg}$
- $250\ \text{kg}$
- $2.6\ \text{kg}$
Show the answer and explanation
Correct answer: A
Step 1: Weight $W = mg$, so mass $m = W/g$. Step 2: $m = 25\,000 / 9.8 \approx 2551\ \text{kg}$, which is $2600\ \text{kg}$ to 2 significant figures.
Question 3
A metal block of weight $890\ \text{N}$ rests on the ground. The face of the block in contact with the ground measures $0.54\ \text{m}$ by $0.18\ \text{m}$. What is the pressure on the ground?
- $9200\ \text{N/m}^2$
- $4900\ \text{N/m}^2$
- $480\ \text{N/m}^2$
- $1230\ \text{N/m}^2$
Show the answer and explanation
Correct answer: A
Step 1: Pressure $p = F / A$. Step 2: Area $A = 0.54 \times 0.18 = 0.0972\ \text{m}^2$. Step 3: $p = 890 / 0.0972 \approx 9200\ \text{N/m}^2$.
Worked answers: questions 4 to 11
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Question 4 · Answer A
Step 1: The lowest possible temperature is the point at which particles have no more kinetic energy to lose. Step 2: This is called absolute zero and equals $-273\ ^\circ\text{C}$ (or $0\ \text{K}$).
Question 5 · Answer A
Step 1: Wave equation: $v = f\lambda$, so $f = v/\lambda$. Step 2: $f = 18 / 1.2 = 15\ \text{Hz}$.
Question 6 · Answer A
Step 1: Dull dark surfaces are good emitters of infrared radiation. Shiny light surfaces are poor emitters. Step 2: The dull black surface radiates more energy per second than the shiny white surface, so the thermometer in front of the dull black surface (X) receives more energy and reaches a higher temperature.
Question 7 · Answer A
Step 1: The light travels there and back, so it covers twice the Earth-Moon distance. Step 2: Total path = $v \times t = 3.0 \times 10^8 \times 2.5 = 7.5 \times 10^8\ \text{m}$. Step 3: One-way distance $= 7.5 \times 10^8 / 2 = 3.75 \times 10^8 \approx 3.8 \times 10^8\ \text{m}$.
Question 8 · Answer A
Step 1: Power: $P = VI$, so $I = P/V$. Step 2: $I = 2000 / 230 \approx 8.7\ \text{A}$.
Question 9 · Answer A
Step 1: Ohm's law gives the p.d. across a resistor: $V = I R$. Step 2: $V = 0.20 \times 20 = 4.0\ \text{V}$.
Question 10 · Answer A
Step 1: Ratio of masses: $60 / 7.5 = 8 = 2^3$, so $3$ half-lives have passed. Step 2: Half-life $= 11.5 / 3 \approx 3.83 \approx 3.8\ \text{days}$.
Question 11 · Answer A
Step 1: The Sun's mass is roughly $\,74\%$ hydrogen and $\,24\%$ helium, with only traces of heavier elements. Step 2: Energy comes from hydrogen fusion: hydrogen nuclei fuse to form helium nuclei.