Extended · structured questions. Each generated paper follows the 0625 Paper 4 · Theory format, with the same number and style of questions as the real exam, and comes with a Cambridge-style mark scheme.
Fig. 1.1 shows a circuit. The battery has negligible resistance.
Fig. 1.1
(a)
Calculate the total resistance of the circuit.
[2]
(b)
Calculate the current in the 15.0 Ω resistor.
[3]
(c)
Calculate the power dissipated in the 2.0 Ω resistor.
[2]
(d)
The 15.0 Ω resistor breaks, so that no current passes through it. State and explain what happens to the reading on the ammeter and to the p.d. across the 2.0 Ω resistor. Support your answer with calculations.
[3]
Show answers and mark scheme
Part
Answer and marking points
Marks
(a)
8 Ω
parallel pair = (1/10 + 1/15)−1 = 6 Ω C1 8 A1
2
(b)
0.3 A
total current = 6 ÷ 8 = 0.75 A C1 p.d. across parallel pair = 0.75 × 6 = 4.5 V C1 0.3 A1
3
(c)
1.13 W
P = I2R C1 1.13 A1
2
(d)
Total resistance increases to 12 Ω, so the ammeter reading falls to 0.5 A; p.d. across 2.0 Ω falls from 1.5 V to 1 V
new total resistance 12 Ω B1 ammeter reading decreases to 0.5 A B1 p.d. across 2.0 Ω decreases (1.5 V → 1 V) B1
3
Question 2Structured · 8 marksA* challenge
A ship uses pulses of ultrasound of frequency 25 kHz to measure the depth of the sea. The speed of sound in sea water is 1500 m/s.
(a)
State what is meant by ultrasound.
[1]
(b)
Calculate the wavelength of the ultrasound in sea water.
[2]
(c)
An echo from the sea bed is received 0.16 s after a pulse is sent. Calculate the depth of the sea.
[2]
(d)
Pulses are sent every 0.50 s. Explain why the ship cannot measure the depth correctly where the sea is deeper than 375 m.
[2]
(e)
State one reason why ultrasound rather than audible sound is used.
[1]
Show answers and mark scheme
Part
Answer and marking points
Marks
(a)
sound with a frequency above 20 kHz (above the upper limit of human hearing)
frequency above 20 kHz / above the range of human hearing B1
1
(b)
0.06 m
λ = v ÷ f with f in Hz C1 0.06 A1
2
(c)
120 m
distance = speed × time, halved for the return journey C1 120 A1
2
(d)
Echoes from deeper than 375 m take longer than 0.50 s to return, so they arrive after the next pulse has been sent and cannot be matched to the correct pulse
echo time > 0.50 s (2 × 375 ÷ 1500) B1 the echo arrives after the next pulse is sent, so it is matched to the wrong pulse B1
2
(e)
Short wavelength gives more detail / can be directed in a narrow beam / does not disturb people
short wavelength, so more detail / narrow beam / inaudible B1
1
Question 3Structured · 9 marks
Water waves are produced in a ripple tank.
(a)
State whether water waves are transverse or longitudinal, and describe the difference.
[3]
(b)
The vibrator has a frequency of 5 Hz and the wavelength is 1.5 cm. Calculate the speed of the waves in m/s.
[2]
(c)
The waves pass into shallower water and slow down. State what happens to the frequency and to the wavelength.
[2]
(d)
The waves pass through a gap in a barrier. State how the width of the gap affects the amount of diffraction.
[2]
Show answers and mark scheme
Part
Answer and marking points
Marks
(a)
transverse; vibrations perpendicular to energy transfer; longitudinal: parallel
water waves are transverse B1 transverse: vibrations at right angles to the direction of energy transfer B1 longitudinal: vibrations parallel to the direction of energy transfer B1
3
(b)
0.0750 m/s
v = fλ = 5 × 0.015 C1 0.0750 m/s A1
2
(c)
frequency unchanged; wavelength decreases
frequency stays the same B1 wavelength decreases B1
2
(d)
most diffraction when gap ≈ wavelength
more diffraction when the gap is narrower B1 greatest when gap is similar to the wavelength B1
2
Question 4Structured · 9 marks
This question is about stars and the Universe.
(a)
Describe the life cycle of a star much more massive than the Sun, after it leaves the main sequence.
[3]
(b)
State the energy source of a main-sequence star and explain why it is stable.
[2]
(c)
Light from distant galaxies is red-shifted. Explain what this means and what it shows.
[2]
(d)
A galaxy is 2.4 × 1024 m away. The Hubble constant is 2.2 × 10−18 per second. Calculate the speed at which it is moving away.
[2]
Show answers and mark scheme
Part
Answer and marking points
Marks
(a)
red supergiant; supernova; neutron star or black hole
becomes a red supergiant B1 explodes as a supernova B1 leaving a neutron star or a black hole B1
3
(b)
nuclear fusion of hydrogen; outward pressure balances gravity
nuclear fusion of hydrogen into helium B1 the outward pressure from the energy released balances the inward pull of gravity B1
2
(c)
wavelength increased; galaxy moving away
the observed wavelength is longer than the emitted wavelength B1 the galaxy is moving away from us B1
2
(d)
5.3 × 106 m/s
v = H₀d = 2.2 × 10−18 × 2.4 × 1024C1 5.3 × 106 m/s A1
2
Question 5Structured · 8 marks
A roller-coaster car of mass 600 kg starts from rest at the top of a slope 30 m above the ground.
(a)
Describe the energy transfers as the car rolls down the slope.
[2]
(b)
Ignoring friction, calculate the speed of the car at ground level.
[3]
(c)
Calculate the speed of the car when it reaches the top of a second hill of height 12 m, ignoring friction.
[2]
(d)
Explain why the speed of the car does not depend on its mass.
[1]
Show answers and mark scheme
Part
Answer and marking points
Marks
(a)
gravitational potential → kinetic, some to thermal (friction)
gravitational potential energy decreases and kinetic energy increases B1 some energy is transferred to thermal energy / sound by friction and air resistance B1
2
(b)
24.2 m/s
mgh = ½mv² C1 v = √(2 × 9.8 × 30) C1 24.2 m/s A1
3
(c)
18.8 m/s
v = √(2 × 9.8 × 18) C1 18.8 m/s A1
2
(d)
m cancels in mgh = ½mv²
both kinetic energy and potential energy are proportional to mass, so mass cancels B1
1
Question 6Structured · 5 marks
A kettle has a metal case connected to the earth wire.
(a)
Explain how the earth wire and fuse protect a user if the live wire touches the case.
[3]
(b)
State two hazards of using electrical appliances.
[2]
Show answers and mark scheme
Part
Answer and marking points
Marks
(a)
large current to earth, fuse melts
a large current flows from the live wire through the case to earth B1 this current melts the fuse B1 the circuit is broken so the case is not live B1
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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