A Level Physics Paper 4 · A Level Structured Questions practice papers
A Level · 100 marks · 2h. Each generated paper follows the 9702 Paper 4 · A Level Structured Questions format, with the same number and style of questions as the real exam, and comes with a Cambridge-style mark scheme.
Sample Paper 4 · A Level Structured Questions questions
Question 1Structured · 8 marksA* challenge
A uranium-235 nucleus absorbs a neutron and undergoes fission: 235U + n → 141Ba + 92Kr + 3n. Masses: U-235 235.0439 u, Ba-141 140.9144 u, Kr-92 91.9262 u, neutron 1.0087 u.
(a)
Calculate the mass defect for this reaction.
[2]
(b)
Calculate the energy released in MeV.
[2]
(c)
Calculate the energy released per kilogram of uranium-235.
[2]
(d)
Explain, using binding energy per nucleon, why energy is released.
[2]
Show answers and mark scheme
Part
Answer and marking points
Marks
(a)
0.1859 u
mass before = 236.0526 u, after = 235.8667 u C1 Δm = 0.1859 u A1
fission products have a higher binding energy per nucleon M1 so the total binding energy increases and the difference is released A1
2
Question 2Structured · 7 marksA* challenge
A cylinder of volume 0.020 m3 contains helium at a pressure of 2.00 × 105 Pa and a temperature of 290 K. The mass of a helium atom is 6.64 × 10−27 kg.
(a)
Calculate the amount of gas and the number of atoms.
[2]
(b)
Calculate the mean kinetic energy of an atom.
[1]
(c)
Calculate the root-mean-square speed of the atoms.
[2]
(d)
Calculate the total kinetic energy of the gas.
[1]
(e)
The thermodynamic temperature is doubled. State the factor by which the rms speed increases.
[1]
Show answers and mark scheme
Part
Answer and marking points
Marks
(a)
1.66 mol; 9.99 × 1023
n = pV/RT = 1.66 mol A1 N = 9.99 × 1023A1
2
(b)
6.00 × 10−21 J
Ek = 3/2 kT = 6.00 × 10−21 J B1
1
(c)
1340 m s−1
½m<c2> = 3/2 kT C1 crms = 1340 m s−1A1
2
(d)
6000 J
3/2 pV = 6000 J B1
1
(e)
√2
√2 (1.41) B1
1
Question 3Structured · 8 marks
In a Millikan-type experiment a charged oil drop of mass 2.0 × 10−15 kg is held stationary between horizontal plates 1.0 cm apart when the p.d. between them is 613 V.
(a)
State the direction of the electric force on the drop and of the electric field if the drop is negatively charged.
[2]
(b)
Calculate the electric field strength between the plates.
[1]
(c)
Use your answer to (b) to calculate the charge on the drop, and the number of electrons it has gained.
[3]
(d)
Explain how results from many drops showed that charge is quantised.
[2]
Show answers and mark scheme
Part
Answer and marking points
Marks
(a)
force upwards; field downwards
electric force upwards (balancing the weight) B1 field downwards, since the force on a negative charge is opposite to the field B1
2
(b)
61300 V m−1
E = V/d = 61300 V m−1B1
1
(c)
3.20 × 10−19 C; 2
qE = mg C1 q = 3.20 × 10−19 C A1 2 electrons A1
3
(d)
all charges were integer multiples of one value, 1.6 × 10⁻¹⁹ C
every charge measured was a whole-number multiple of a smallest value B1 1.60 × 10−19 C (the elementary charge) B1
2
Question 4Structured · 4 marks
Define the tesla and Faraday’s law.
(a)
Define the tesla.
[2]
(b)
State Faraday’s law and Lenz’s law.
[2]
Show answers and mark scheme
Part
Answer and marking points
Marks
(a)
force per unit current per unit length
the magnetic flux density where a wire carrying 1 A normal to the field experiences a force of 1 N per metre length B2
2
(b)
emf ∝ rate of change of flux linkage; direction opposes change
Faraday: induced e.m.f. is proportional to the rate of change of magnetic flux linkage B1 Lenz: the induced e.m.f. acts to oppose the change producing it B1
2
Question 5Structured · 8 marks
The count rate from a radioactive sample is measured every hour. The background count rate is 60 counts per minute. Table 5.1 shows the results.
time / hours
0
1
2
3
4
5
6
count rate / counts per minute
1660
1273
979
756
588
460
363
Table 5.1
(a)
Define the decay constant.
[1]
(b)
Use Table 5.1 to determine the half-life of the sample. Show your working.
[3]
(c)
Use your answer to (b) to calculate the decay constant in s⁻¹.
[2]
(d)
Explain why the background count rate must be subtracted.
[1]
(e)
Repeated measurements of the count rate at the same time give slightly different values. Explain why.
[1]
Show answers and mark scheme
Part
Answer and marking points
Marks
(a)
probability per unit time that a nucleus decays
the probability per unit time that a nucleus will decay B1
1
(b)
2.50 hours
subtract background: corrected rates 1600 … C1 time for corrected rate to halve / gradient of ln(corrected rate) against t C1 2.50 hours (± 0.1) A1
3
(c)
7.70 × 10−5 s−1
λ = ln 2 ÷ t½, with t in seconds C1 7.70 × 10−5 s−1A1
2
(d)
background not from source; would make decay appear slower
Any 1 of: background radiation is not from the sample; including it gives too large a count rate / too long a half-life B1
1
(e)
decay is random
radioactive decay is random (spontaneous), so the number of decays in each interval varies B1
1
Question 6Structured · 3 marks
A mass of 1.5 kg moves in a horizontal circle of radius 0.8 m with a period of 0.9 s. Calculate the centripetal force.
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Original Cambridge-style practice questions written for mentorriyaz.in. These are not Cambridge past paper questions, and this site is not affiliated with or endorsed by Cambridge University Press & Assessment. Updated 2026-11-04. Paper generator · mentorriyaz.in