Questions 1
This is a question about reflection.
(a) Which diagram shows a light ray correctly reflected from a mirror?
(b) Name the equipment needed to measure the angle of incidence on a ray diagram.
(c) Light from a laser on the Earth reflects off special mirrors on the Moon. The graph shows the data from a light sensor attached to the laser. The first peak shows when the light leaves the laser and the second peak shows when the light has returned from the Moon.
(i) Determine the time taken for the light to travel from the Earth to the Moon and back again.
(ii) The speed of light is \(3.0×10^5 km/s\). Calculate the total distance travelled by the light from the laser.
[average speed = distance moved ÷ time taken]
(iii) Calculate the distance from the Earth to the Moon.
▶️Answer/Explanation
Ans
(a) C;
A cannot be correct as the angle of reflection is not equal to the angle of reflection.
B and D cannot be correct as the ray penetrates into the mirror rather than reflects.
(b) protractor;
(c) (i) attempt at measuring the (time) difference between the two peaks;
2.5 s;
(ii) substitution and rearrangement into given eqn;
evaluation;
correct answer: 750 000 (km)
e.g. distance = speed × time
distance = 300 000 × 2.5
distance = 750 000 (km)
(iii) division of candidate’s answer for (ii) by 2;
correct answer: 375 000 (km)
Questions 2
The diagram shows the orbit of the Earth around the Sun.
(a) (i) Draw the orbit of the Earth’s Moon on the diagram.
(ii) Draw the orbit of a comet on the diagram.
(b) Earth orbits the Sun in 365 days with an orbital radius of 150000000km. Calculate the Earth’s orbital speed in km/s.
(c) Which force keeps the Earth in orbit around the Sun?
A electrostatic
B gravitational
C magnetic
D nuclear
(d) Describe the evolution of the Sun from the first stage of its evolution to the final stage of its evolution.
▶️Answer/Explanation
Ans
(a) (i) any orbit around Earth;
circular orbit centred on Earth;
(ii) any elliptical orbit around Sun;
with focus at Sun;
(b) evidence of correct conversion from days to seconds;
substitution into given formula;
correct evaluation;
Correct answer: 30 km/s
e.g.
\(365 × 24 × 60 × 60 = 31.5 × 10^6s\)
Orbital speed = (2 π r ) ÷ T
Orbital speed = \(( 2 x π ×150 000 000) / 31.5…. × 10^6s\)
Orbital speed = 29.9 km/s
(c) B – gravitational;
A, C and D cannot be correct as only the gravitational force is responsible for keeping planets in orbit around their star.
(d) starts as nebula/cloud (of gas);
reference to main sequence;
finishes as white dwarf;
PLUS at least ONE, in the correct place, from protostar/red (super) giant/planetary nebula;
e.g.
nebula → protostar → main sequence → red giant → white dwarf and planetary nebula
Questions 3
The diagram shows a balloon with a mass attached held at rest just below the surface of a deep pool of water.
(a) The balloon and mass are released. The graph shows the velocity-time graph for the balloon and mass as they fall through the water
(i) Use information from the graph to determine the terminal velocity of the balloon and mass.
(ii) Explain how the balloon reaches terminal velocity. You should use ideas about forces acting on the balloon in your answer.
(b) (i) State the formula linking pressure difference, height, density and gravitational field strength.
(ii) Calculate the increase in pressure on the balloon when it has reached a depth of 25m in the water.
[for water, density = \(1000kg/m^3\)]
(iii) At the surface, the atmospheric pressure on the balloon is \(1.0×10^5 Pa\). Show that the total pressure on the balloon at a depth of 25m is \(3.5×10^5 Pa\).
(iv) At the surface, where the pressure is \(1.0×10^5 Pa\), the balloon has a volume of \(0.46m^3\). Calculate the volume of the balloon at a depth of 25m.
▶️Answer/Explanation
Ans
(a) (i) 8.2 (m/s) ;
(ii) any TWO from:
MP1. reference to weight and drag;
MP2. weight greater than drag;
MP3. resultant force causes acceleration;
MP4. drag increases with speed;
PLUS
weight = drag at terminal velocity/eq;
(b) (i) pressure difference = height × density × g ;
(ii) substitution;
evaluation;
correct answer: 250 000 (Pa)
e.g. pressure difference = height × density × g
pressure difference = 25 × 1000 × 10
pressure difference = 250 000 (Pa)
(iii) addition of \(1.0 × 10^5\) to candidate’s answer to (ii);
correct answer: \(3.5 × 10^5 (Pa)\)
(iv) substitution into given equation;
rearrangement;
correct evaluation;
correct answer: 0.13(14) \((m^3)\)
e.g. \(p_1 × V_1 = p_2 × V_2\)
\(1.0 × 10^5 × 0.46 = 3.5 × 10^5× V_2\)
\(V_2 = (1.0 × 10^5× 0.46) ÷ (3.5 × 10^5)\)
\(V_2 = 0.1314 (m^3)\)
Questions 4
A student investigates how the current in a filament lamp varies with the voltage across it. The student has this equipment
• filament lamp
• cell
• variable resistor
• ammeter
• voltmeter
• connecting wires
(a) Draw a circuit diagram that the student could use for this investigation.
(b) The table gives the student’s results.
(i) Plot the results on the grid.
(ii) Draw the curve of best fit.
(c) The filament of the lamp is made of metal. The student suggests that a straight line on the graph is more appropriate than a curve because current is directly proportional to voltage for a metal.
(i) Suggest how the student could improve their investigation to find out whether a straight line or curve is more appropriate.
(ii) Explain why the student should not expect current to be proportional to voltage for this filament lamp.
▶️Answer/Explanation
Ans
(a) correct symbols for all components;
components connected in a series circuit;
ammeter in series with lamp;
voltmeter in parallel with lamp;
(b) (i) all points plotted correctly;
(ii) curve passes within half a small square of all points;
(c) (i) idea of taking more data at different voltages;
(ii) any TWO from:
MP1. current (in filament) heats up the filament;
MP2. resistance changes with temperature;
MP3. idea that change of resistance affects gradient (of graph);
Questions 5
The photograph shows the nuclear fusion reactor called ITER.
(a) Describe the difference between nuclear fusion and nuclear fission.
(b) At ITER, hydrogen-3 and hydrogen-2 will be fused into helium and another particle labelled X.
(i) Complete the nuclear equation for the fusion of hydrogen-3 and hydrogen-2. 
(ii) Discuss potential safety advantages of a fusion reactor compared with a fission reactor. You should refer to the products of this fusion reaction and to the fission reaction of uranium.
(c) The half-life of a radioactive isotope is 12 years. The activity of a sample of this isotope is 120kBq. Calculate the activity of this sample after 48 years.
▶️Answer/Explanation
Ans
(a) fission is the splitting of a nucleus;
fusion is the joining of (two) nuclei;
(b) (i) mass number = 1;
atomic number = 0;
(ii) any THREE from:
MP1. idea that reactants are not (as) hazardous for fusion;
MP2. idea that products of fusion are not radioactive;
MP3. (so) no {mutations/damage to cells/tissue/cancer} ;
MP4. (so) no long-term storage problems;
MP5. idea that no shielding is required;
MP6. idea of lower or no risk of meltdown for fusion;
MP7. idea that there is no runaway chain reaction for fusion;
(c) evidence of activity halved;
evidence of activity halved four times only;
correct evaluation;
correct answer: 7.5 (kBq)
e.g. 120 ÷ 2 = 60
60 ÷ 2 = 30
30 ÷ 2 = 15
15 ÷ 2 = 7.5
Questions 6
The diagram shows a small computer in two difference cases, X and Y. The electronic chip in the computer is hot when in use. Each case is designed to cool the computer chip.
Case X is made of white plastic and has a fan.
Case Y is made of black-painted aluminium metal and has no fan. There is a metal block that is in contact with the case and the chip.
(a) Explain the main method of heat transfer from the chip to the surroundings for case X.
(b) Explain the main method of heat transfer from the chip to the surroundings for case Y.
(c) (i) State the formula linking power, current and voltage.
(ii) The small computer operates at a voltage of 5.1V with a current of 2.9A. Calculate the power of the small computer. Give the unit.
▶️Answer/Explanation
Ans
(a) any THREE from:
MP1. correct reference to convection;
MP2. fan aids convection;
MP3. reference to conduction not being the main method;
MP4. (since) {plastic/air} is a poor conductor/good insulator;
MP5. white (materials) are poor at emitting /eq;
(b) any THREE from:
MP1. correct reference to conduction;
MP2. since {metals/aluminium} conducts well;
MP3. reference to convection not being the main method;
MP4. as hot air particles can’t circulate (from inside to outside);
MP5. black (materials) are good at emitting/eq;
(c) (i) power = voltage × current;
(ii) substitution;
evaluation;
watt or W as the unit;
correct answer: 15 watts
e.g. power = voltage × current
power = 5.1 × 2.9
power = 14.8 watts
Questions 7
The diagram shows the path of a ray of light.
(a) (i) Measure the angle of incidence for the ray at point K. Which of these is the angle of incidence?
A 43°
B 47°
C 51°
D 55°
(ii) State the formula linking refractive index, angle of incidence and angle of refraction.
(iii) The block has a refractive index of 1.52. Use the formula to show that the angle of refraction is about 30° for the ray at point K.
(b) (i) The refractive index of the block is 1.52. Calculate the critical angle of the block.
(ii) State what happens to the ray at point L.
▶️Answer/Explanation
Ans
(a) (i) C – 51°;
Angle should be measured and cannot be either A, B or D.
(ii) refractive index = sin (i)/sin (r);
(iii) substitution;
rearrangement;
correct evaluation;
correct answer: 31 degrees
e.g
refractive index = sin (i)/sin (r)
1.52 = sin(51)/sin(r)
sin(r) = sin(51)/1.52
sin(r) = 0.511…
r = sin-1(0.511…) = 30.7… degrees
(b) (i) use of formula sin c = 1/n;
substitution;
correct evaluation;
correct answer: 41 (degrees)
e.g.
sin c = 1/n
sin c = 1/1.52
c = sin−1(1/1.52) = 41.1 (degrees)
(ii) total internal reflection (TIR) / angle of incidence is above the critical angle and so reflects;
Questions 8
A student wants to determine the density of air using an irregularly-shaped balloon made of metal foil. The balloon has a label stating that the volume of the balloon when full is \(490cm^3\). This is part of the student’s method.
Step 1 measure the mass of the empty balloon
Step 2 fill the balloon with air
Step 3 measure the mass of the full balloon
Step 4 subtract the mass of the empty balloon from the mass of the full balloon.
(a) (i) Name the equipment the student could use to measure the mass of the balloon.
(ii) Suggest how the student could improve the reliability of their data.
(b) The table shows the student’s results.
Calculate the density of air to 2 significant figures. Give the unit.
(c) Describe how the volume of the balloon full of air could be measured using a large beaker and some water. You may use a diagram to help your answer.
▶️Answer/Explanation
Ans
(a) (i) balance;
(ii) take repeats and either find mean, identify or remove anomalies;
(b) mass of air is 0.61 g;
correct use of formula: density = mass/volume;
correct evaluation to 2 sf;
appropriate unit i.e. \(g/cm^3\);
correct answer = \(0.0012 g/cm^3\)
e.g.
mass of air = 15.61 − 15.00 = 0.61
density = mass ÷ volume
density = 0.61 ÷ 490
density = 0.00124 \(g/cm^3\)
density = 0.0012 \(g/cm^3\) to 2 sf
(c) any THREE from:
MP1. any reference to displacement method;
MP2. measure original volume of water;
MP3. (fully) submerge balloon;
MP4. re-measure volume of water;
MP5. subtract one volume from the other;
Questions 9
A teacher demonstrates the penetrating ability of alpha, beta and gamma radiation from some radioactive sources.
(a) (i) State a precaution the teacher should take to make sure they are working safely with the radioactive sources.
(ii) State the name of a detector the teacher could use to detect the radiation from each source.
(b) Draw crosses (×) in the table to show which type of radiation cannot penetrate each material in the table.
(c) An alpha particle of mass \(6.6×10^{–27} kg\) travelling at a speed of \(2.1×10^7 m/s\) hits a sheet of paper.
(i) Calculate the kinetic energy (KE) of the alpha particle.
(ii) State the work done on the alpha particle when its speed is reduced to 0 m/s by the sheet of paper.
(iii) State which energy store of the paper increases when the alpha particle is stopped.
▶️Answer/Explanation
Ans
(a) (i) any ONE from:
wear gloves;
use tongs;
do not point source at anyone;
keep source at arm’s length;
keep source in lead-lined box;
keep exposure time short;
wear goggles;
lead apron;
(ii) Geiger-Muller tube (and counter);
(c) (i) recall of KE = \(\frac{1}{2} m v^2\);
substitution;
correct evaluation;
correct answer: \(1.5 × 10^{−12} (J)\)
e.g.
KE = \(\frac{1}{2} m v^2\)
KE = \(\frac{1}{2} × (6.6 × 10^{−27}) × (2.1 × 10^7)^2\)
KE = \(1.4553 \times 10^{−12} (J)\)
(ii) candidate’s answer for (i)
e.g. \(1.5 × 10^{−12} (J)\)
(iii) thermal;
Questions 10
The diagram shows the forces acting on a firework at take-off.
(a) (i) Calculate the magnitude of the resultant force on the firework.
(ii) State the formula linking resultant force, mass and acceleration.
(iii) The mass of the firework is 160g. Calculate the acceleration of the firework.
(iv) Explain how the acceleration of the firework changes between take-off and running out of fuel. You can assume that the thrust force stays the same as the firework burns the fuel.
(b) The firework makes a sound with constant frequency. As the firework moves upwards, people on the ground notice that the frequency of the sound they hear changes. This is called the Doppler effect. Explain how the Doppler effect causes the observed frequency of sound to change for the people on the ground.
▶️Answer/Explanation
Ans
(a) (i) 26(.4) (N) ;
(ii) (resultant) force = mass × acceleration;
(iii) conversion of 160 g to 0.16 kg;
rearrangement or substitution;
correct evaluation;
correct answer: \(165 (m/s^2)\)
e.g. acceleration = resultant force ÷ mass
acceleration = 26.4 ÷ 0.16
acceleration = \(165 (m/s^2)\)
(iv) any THREE from:
MP1. weight decreases;
MP2. air resistance increases;
MP3. consistent inference of changing resultant force;
MP4. (therefore) changing acceleration;
(b) any FOUR from:
MP1. (observed) frequency decreases;
MP2. speed of waves constant;
MP3. wavefronts behind firework spread out/eq;
MP4. causing an increased wavelength (at the observer);
MP5. reference to f = speed ÷ wavelength;
Questions 11
The diagrams show some equipment that the physicist Ørsted used in an investigation in 1820. Diagram 1 shows the position of eight compass needles around a wire with no current in the wire. The compass needles line up with and show the direction of the Earth’s magnetic field lines.
Diagram 2 shows the position of the same compass needles when a current is in the wire. 
(a) (i) Explain why the compass needles turn when the current is switched on.
(ii) Using evidence from the compass needles in diagram 2, draw on diagram 2 the shape and direction of a magnetic field line produced by the current in the wire.
(iii) Suggest what happens to the magnetic field when the current in the wire is reversed.
(b) The current in the wire is turned off. Diagram 3 shows the wire placed in a uniform magnetic field.
The current is now switched on. Draw an arrow to show the direction of the force on the wire.
(c) The power supply in diagram 3 is replaced by an ammeter.
(i) When the wire is moved, a current is detected. Explain which direction the wire is moved in the magnetic field to produce a current in the wire.
(ii) Explain why a current is produced in the wire when the wire is moved in the magnetic field.
▶️Answer/Explanation
Ans
(a) (i) current provides a magnetic field/eq;
magnets in a magnetic field experience a force/magnets line up along a field line/eq;
(ii) (circular) field line through all of the compass needles;
arrow clockwise;
(iii) changes direction / eq;
(b) vertical;
upwards;
(c) (i) up / down;
idea of cutting field lines;
(ii) cutting field lines induces a voltage across the wire;
complete circuit so voltage gives a current;