0625/51 — Paper 5 Practical Test
Cambridge Assessment International Education · October/November 2025
- DOCUMENTS
- CI · QP · MS
- TOTAL PAGES
- 34
- QUESTIONS
- 17
- MARKS
- 40
WHAT THIS PAPER ASKS YOU TO DO
Moments: finding the weight of an unknown mass
Balance a metre ruler pivoted on a triangular block against an unmarked mass Q, using 2.0 N and 3.0 N reference loads, and use moments to find Q's weight.
- 1(a), (b)(i)With the ruler pivoted at the 50.0 cm mark and object Q centred at the 90.0 cm mark, determine the distance y from the 50.0 cm mark to the centre of Q [2]. Then place the 2.0 N load on the ruler, adjust its position until the ruler is as near as possible to balanced, and determine the distance x from the centre of the load to the 50.0 cm mark [1].[3]
- 1(b)(ii)Calculate the weight W of object Q, using the equation W = (x / y) × 2.0 N. Give your answer to a suitable number of significant figures for this experiment.[2]
- 1(c)Remove the 2.0 N load without moving object Q. Repeat the balancing procedure with the 3.0 N load and record y, x and W = (x / y) × 3.0 N.[2]
- 1(d)State and explain whether your two values of W are equal within the limits of experimental accuracy. Refer to the values of W in your answer.[2]
- 1(e)Explain how you ensure that the centre of object Q is directly over the 90.0 cm mark of the metre ruler. You may draw a diagram.[1]
- 1(f)It is difficult to find the position of the load to obtain the exact balance of the metre ruler. Explain how you try to overcome this difficulty.[1]
Resistance of a wire (slide-wire potentiometer)
Slide a contact along ~105 cm of taped-down constantan wire, reading current and the p.d. across increasing lengths BC, to find how resistance depends on length.
- 2(a)Close the switch. Measure the current I in the circuit. Include the unit.[1]
- 2(b)(i), (b)(ii), (c)Place the sliding contact at d = 20.0 cm from B and measure the p.d. V across BC; record d and V in Table 2.1, open the switch, then calculate R = V / I and record it [2]. Close the switch and repeat for d = 40.0, 60.0, 80.0 and 100.0 cm [3].[5]
- 2(b)(iii)Complete the column headings in Table 2.1.[1]
- 2(d)Plot a graph of resistance R/Ω (y-axis) against length d/cm (x-axis). Draw a best-fit line.[4]
Refraction through a rectangular glass block
Trace an incident ray into a glass block with optics pins, find the emergent ray by sighting through it, and measure the equivalent angle on both sides of the normal.
- 3(a)Place the block on the ray-trace sheet, draw and label its outline ABCD. Remove the block and draw the normal NL to side AB, 2.0 cm from A, continued through side CD. Label the point Q where NL crosses AB.[2]
- 3(b)Draw line PQ at angle of incidence i = 30° to the normal. Place pins P1 and P2 on PQ. Replace the block and, sighting through side CD, place pins P3 and P4 so that P3, P4 and the images of P1, P2 appear exactly one behind the other. Label P1–P4 and remove the pins.[3]
- 3(c)Draw a line through P3 and P4, continue it until it meets NL, and label that point E; label the other end F. Measure the acute angle θ between EF and the normal.[2]
- 3(d)Repeat the procedure in (b) and (c) using an angle of incidence i = 45° to obtain a new value of angle θ.[1]
- 3(e)Tick one box to complete the sentence: 'To produce the most accurate ray-trace, a student places the pins P1 and P2 ...'[1]
- 3(f)A student plans to investigate the relationship between angle i and angle θ, taking more sets of readings. List suitable values of angle i that the student can use.[2]
Planning: comparing electrical heaters
Written only — plan an experiment comparing how quickly five 12 V heaters bring water to the boil.
- 4A student thinks some of five identical 12 V heaters are more efficient than others. Plan an experiment to compare how quickly the heaters increase the temperature of water to boiling point, using electrical heaters, beakers, a supply of water and a 12 V power supply, plus any other normal laboratory apparatus. You are not required to do the experiment: list additional apparatus, explain how you'd carry out the investigation and the measurements taken, state the key variables to keep constant, draw a suitable results table (headings only), and explain how you'd reach a conclusion.[7]
What the lab technician is told: exact solutions, concentrations and apparatus to set out. This is where the bench comes from.
QUESTION 1 — MOMENTS APPARATUS
The candidate is not told the mass or weight of object Q.
- metre ruler— with a mm scale; a second scale, if present, is taped over1
- triangular block— acts as a pivot for the ruler, stands on the bench1
- object Q— a 200 g mass; its weight must not be visible to the candidate1
- 2.0 N load— a 200 g mass labelled 2.0 N1
- 3.0 N load— a 300 g mass labelled 3.0 N1
QUESTION 2 — RESISTANCE-OF-A-WIRE APPARATUS
Circuit pre-assembled for the candidate, as in Fig. 2.1.
- power supply— approximately 1.5–3 V; output voltage fixed by the supervisor (e.g. taped)1
- switch— may be integral to the power supply1
- ammeter— reads up to 1.00 A, resolution at least 0.05 A1
- voltmeter— measures the supply p.d., resolution at least 0.1 V1
- constantan (Eureka) resistance wire— approx. 105 cm, 0.28 mm diameter (32 swg) or similar, ~8 Ω/m, bare, taped to the metre ruler only between the 3–7 cm and 93–97 cm marks1
- terminals B and C— crocodile clips at the wire ends: B at the zero end, C at the 100 cm end2
- sliding contact S— a jockey, or a small screwdriver on a lead with a crocodile clip1
- connecting leads— sufficient to wire the circuit shown in Fig. 2.1
QUESTION 3 — REFRACTION APPARATUS
Ray-trace sheet is tied into the candidate's booklet between pages 6 and 7.
- ray-trace sheet— plain A4 paper with a hole in one corner, for tying into the booklet1
- transparent block— rectangular glass or Perspex, approx. 10 cm × 6 cm × 1.5 cm1
- optics pins4
- pin board— e.g. a cork mat, A4 size or larger1
- protractor— candidates may use their own
- 30 cm or 50 cm ruler— graduated in mm; candidates may use their own
- string or treasury tag— to tie the ray-trace sheet into the booklet
⚠ No hazardous substances are used anywhere on this paper — it is apparatus-only. The supervisor performs each experiment out of sight of candidates beforehand and records supervisor's results, including a ray-trace sheet for Question 3.
THE CURATED BENCHES BUILT FROM THIS
Same skills, taught rather than examined — guided step by step, with the apparatus mistakes explained as you make them.