Questions 1
The diagram is an incomplete Hertzsprung‑Russell diagram which astronomers use to compare stars.
(a) The y‑axis label is missing. Which of these is the correct label for the y‑axis?
A absolute magnitude
B apparent magnitude
C scalar magnitude
D vector magnitude
(b) The box contains words to identify the shaded areas P, Q and R on the Hertzsprung‑Russell diagram.
Use words from the box to identify P, Q and R.
(c) Explain which side of the diagram contains stars with the highest surface temperature.
▶️Answer/Explanation
Ans
(a) A (absolute magnitude);
B is incorrect because apparent magnitude is how bright the star appears on Earth, regardless of distance
C is incorrect because the H-R diagram requires a specific scalar magnitude
D is incorrect because the H-R diagram requires a specific magnitude
(b) P: white dwarfs;
Q: main sequence;
R: red giants;
(c) idea of the left-hand side;
idea that blue/white stars are hottest / hotter than red/orange stars;
Questions 2
This is a question about electromagnetic waves.
(a) State which colour in the visible spectrum has the shortest wavelength.
(b) Explain a hazard of ultraviolet radiation to the human body.
(c) (i) State the formula linking speed, wavelength and frequency of a wave.
(ii) Calculate the frequency of radio waves with a wavelength of 15m.
[speed of light = 300000000m/s]
▶️Answer/Explanation
Ans
(a) violet;
(b) idea that UV causes mutations/damage (in cells);
(leading to) (skin) cancer/blindness;
(c) (i) speed = frequency × wavelength;
(ii) substitution OR rearrangement;
evaluation;
e.g.
300 000 000 = f × 15 OR f = v/λ
(f =) 20 000 000 (Hz)
Questions 3
A tumble dryer is a household device that dries clothes. The clothes rotate in a heated cylinder. Clothes often stick together when they are dry because they become electrostatically charged. A student investigates how different materials charge electrostatically in a model tumble dryer. The diagram shows the model tumble dryer.
This is the student’s method.
• put four dry squares of the same material into the cylinder
• rotate the cylinder at constant speed for three minutes
• remove any squares that are stuck together
• measure the force needed to pull the squares apart
• repeat this for squares of different material
(a) (i) Name a device the student could use to measure a force.
(ii) State the independent and dependent variables in this investigation.
(iii) State a control variable in this investigation.
(b) Explain how the squares of material stick together. Use ideas about electrostatic charge in your answer.
(c) The table shows some of the student’s results.
Explain which type of graph is the most appropriate to present the results from this investigation.
(d) (i) State the formula linking charge, current and time.
(ii) When the squares of material are pulled apart there is a small spark. There is a current of \(4.3×10^{–6}A\) in the air for a time of \(2.3×10^{–3} s\). Calculate the charge that is transferred.
▶️Answer/Explanation
Ans
(a) (i) newtonmeter;
(ii) independent: material (of the squares);
dependent: force;
(iii) any one from:
* speed (of rotation);
* direction of rotation;
* temperature (of tumble dryer);
* number of squares;
* size / thickness / shape of square;
* time (of rotation);
(b) any three from:
MP1. idea of friction (between pieces of material);
MP2. electrons/charge transferred between squares/material;
MP3. squares become oppositely charged;
MP4. square is negative if electrons gained;
MP5. idea that opposite charges attract;
(c) bar chart;
idea that material/data is categoric;
(d) (i) charge = current × time (taken);
(ii) substitution;
evaluation;
e.g.
\(Q = 4.3 × 10^{−6} × 2.3 × 10^{−3}\)
\((Q =) 9.9 × 10^{−9} (C)\)
Questions 4
Diagram 1 shows a circuit built by a student.
(a) (i) State the formula linking voltage, current and resistance.
(ii) Calculate the voltage across the 17Ω resistor.
(iii) State the voltage across the 6.2Ω resistor.
(iv) Calculate the current in the battery.
(b) Diagram 2 shows a second circuit built by the student using the same battery and resistors.
Explain how the current in the battery will change now the resistors are connected in series. You do not need to do any calculations in your answer.
▶️Answer/Explanation
Ans
(a) (i) voltage = current × resistance;
(ii) conversion of mA to A;
substitution;
evaluation;
e.g.
83 ÷ 1000 = 0.083
V = 0.083 × 17
(V =) 1.4 (V)
(iii) 1.4 (V)
(iv) evidence of addition of the two currents;
311 mA;
(b) any three from:
MP1. current decreases;
MP2. (total) resistance increases;
MP3. idea that total voltage is the same;
MP4. reference to V=IR;
Questions 5
A transformer is used to charge a mobile phone. The diagram shows a label on the transformer.
(a) Explain how the information in the label shows that the transformer is a step‑down transformer.
(b) Show that the transformer is approximately 100% efficient.
(c) (i) State the formula linking input voltage, output voltage and turns ratio for a transformer.
(ii) The primary coil has 1500 turns. Calculate the number of turns on the secondary coil.
▶️Answer/Explanation
Ans
(a) output voltage is less than input voltage;
output current is greater than input current;
(b) any attempt to calculate a power;
correct calculation of either input or output power;
indication that the input and output power are (approximately) equal;
e.g.
input power = 230 × 0.067
input power = 15(.41)
15(.41) ≈ 15(.5)
(c) (i) \(N_p/N_s = V_p/V_s\);
(ii) substitution;
rearrangement;
evaluation to 2 s.f. or more;
e.g.
\(1500/N_s = 230/5.0\)
\((N_s =) 1500 / (230 / 5.0)\)
\((N_s =) 33\)
Questions 6
This question is about the use of water in central heating systems.
(a) A student does an investigation to find the specific heat capacity of water. This is the list of equipment they use.
• heater with a power output of 50 W
• power supply
• beaker
• water
• thermometer
• stopwatch
• connecting leads
• balance
Describe an investigation the student could use to find the specific heat capacity of water. You may draw a diagram to help your answer.
(b) The diagram shows a simplified central heating system viewed from above.
Pipes transport hot water around a house to radiators and back to the boiler. The boiler heats water from 16°C to 65°C.
(i) Calculate the energy transferred from the boiler to 75kg of water to raise the temperature of the water from 16°C to 65°C.
[for water, specific heat capacity = 4200J/kg°C]
(ii) The radiators transfer energy from the water to the air in the house. The temperature of the water in the heating system decreases by 4°C due to heat transferred to the air. This causes the air in the house to increase in temperature by 15°C. The mass of air in the house and the mass of water in the heating system are approximately the same. Explain why there is a larger temperature change in the air.
▶️Answer/Explanation
Ans
(a) any five from:
MP1. measure temperature increase;
MP2. measure time taken;
MP3. allow temperature to rise to maximum after heater switched off;
MP4. calculate total energy / use of E = P×t;
MP5. measure mass of water;
MP6. (by) finding difference between empty beaker and ‘beaker + water’
MP7. use of E = m × c × Δθ;
MP8. plot a temperature-time graph;
MP9. use gradient (so c = P/(m × gradient);
(b) (i) temperature difference calculated;
substitution;
evaluation;
e.g.
(∆T = 65 – 16 =) 49 (°C)
∆Q = 75 × 4200 × 49
(∆Q =) 15 000 000 (J)
(ii) any three from:
MP1. idea that energy/heat lost by water is approximately equal to energy gained by air;
MP2. (some) thermal energy lost to the surroundings;
MP3. air and water have a different specific heat capacity;
MP4. air has a smaller heat capacity than water;
MP5. valid attempt to show algebraically;
MP6. correct algebraic attempt;
Questions 7
A crumple zone is a safety feature in a car. It is a part of the car that is designed to collapse during a collision. A student investigates the effectiveness of crumple zones. The student rolls two model cars down a ramp. Each car comes to rest when it hits a large metal block. A data logger measures the mean force applied to the car during the collision with the block. The diagram shows the equipment used in the investigation.
Car 1 has a paper crumple zone at the front.
Car 2 has no paper crumple zone.
The table shows the student’s results. 
(a) The mass of each car is 0.074kg. Calculate the time taken for the velocity of car 1 to decrease from 3.0m/s to 0.0m/s.
(b) State the magnitude and direction of the force on the metal block, when car 2 collides with the block.
(c) Explain why the mean force from the block on car 1 is smaller than the mean force on car 2.
▶️Answer/Explanation
Ans
(a) substitution into F = (mv − mu) / t;
rearrangement;
evaluation;
e.g.
2.5 = [0.074 × 3.0 (−0.074 × 0.0)] / time
time = (0.074 × 3.0) / 2.5
(time =) 0.089 (s)
(b) magnitude = 4.9 (N);
direction = right/opposite to car;
(c) any two from:
MP1. (crumple zone) increases the time (taken to
stop);
MP2. same momentum change (as car 2);
MP3. smaller acceleration; allow deceleration
MP4. reference to formula force = change in momentum/time;
Questions 8
Between 1929 and 1931, physicists Hubble and Humason investigated the red‑shift of light from galaxies at different distances from the Earth. The distance unit they used is the megaparsec (Mpc).
(a) Describe what is meant by the term red‑shift.
(b) The graph shows some of the results of their investigation.
(i) Draw a circle to show the anomalous data point.
(ii) Draw the line of best fit on the graph.
(iii) The reference wavelength of the light used in this investigation is 660nm. Use information from the graph to determine the velocity of a galaxy at a distance of 0.75Mpc.
[speed of light = 300000km/s]
(iv) Explain why the graph from Hubble’s investigation provides evidence for the expansion of the universe.
▶️Answer/Explanation
Ans
(a) increase in wavelength (of wave);
due to source/galaxy moving away (from observer)/eq;
(b) (i) point at (0.5,0.03) identified;
(ii) straight line drawn within 1 small square of each data point;
(iii) change in wavelength = 0.03 (nm);
substitution OR rearrangement;
evaluation;
e.g.
change in wavelength = 0.03 (nm)
0.03/660 = v/300 000 OR v = ∆λ/λ × c
(v =) 14 (km/s)
(iv) any two from:
MP1. change in wavelength increases with distance (from Earth or Milky Way);
MP2. idea that (recession) velocity increases with distance (from Earth or Milky Way);
MP3. galaxies are all moving away from each other;