Total marks: 100 · Duration: 105 minutes · Tier: Higher
Instructions to candidates
- Use black ink or ball-point pen.
- Answer all questions.
- In calculations, show all your working and give the unit of your answer.
- You may use a calculator.
- For multiple-choice parts, choose one answer, A, B, C or D.
- Where a question describes a graph, circuit or apparatus in words, you may find it helpful to sketch it.
Information
- The total mark for this paper is 100.
- The marks for each question are shown in brackets.
- In questions marked with an asterisk (*), marks will be awarded for your ability to structure your answer logically, showing how the points that you make are related or follow on from each other where appropriate.
- This paper covers Edexcel GCSE (9–1) Physics Paper 2 content: topic 1 (key concepts of physics) and topics 8 to 15: energy – forces doing work; forces and their effects; electricity and circuits; static electricity; magnetism and the motor effect; electromagnetic induction; particle model; and forces and matter.
- Take the gravitational field strength g = 10 N/kg.
- Equations you may need that are on the Edexcel physics equations list: energy transferred = current × potential difference × time; force on a conductor = magnetic flux density × current × length; potential difference across primary coil × current in primary coil = potential difference across secondary coil × current in secondary coil; energy transferred in stretching = ½ × spring constant × (extension)².
Paper
Question 1 — Work, power and efficiency (10 marks)
(a) Which is the unit of power? [1 mark]
A joule B newton C pascal D watt
(b) A building-site crane lifts a load of mass 450 kg vertically through 12 m in 30 s.
(i) Calculate the work done on the load. [2 marks]
(ii) Calculate the useful power output of the crane. [2 marks]
(iii) The input power to the crane's motor is 2400 W. Calculate the efficiency of the crane. [2 marks]
(c) A worker pushes a crate 6.0 m across a level floor with a steady horizontal force of 80 N.
(i) Calculate the work done by the worker. [2 marks]
(ii) State what happens to the energy transferred by the worker. [1 mark]
Question 2 — Forces and their effects (10 marks)
(a) A small boat's engine pushes it east with a force of 300 N. A river current pushes it north with a force of 400 N. Calculate the size of the resultant force on the boat. [2 marks]
(b) A uniform plank is balanced on a pivot at its centre to make a seesaw. Child A, of weight 400 N, sits 1.5 m from the pivot. Child B, of weight 600 N, sits on the other side.
Calculate how far from the pivot child B must sit for the seesaw to balance. [3 marks]
(c) A mechanic applies a force of 40 N at right angles to the end of a spanner. The distance from the nut to the end of the spanner is 0.25 m.
(i) Calculate the moment of the force about the nut. [2 marks]
(ii) Explain why a longer spanner makes a tight nut easier to undo. [1 mark]
(d) In a machine, a driving gear with 12 teeth turns a driven gear with 36 teeth. Describe how the speed of rotation and the turning effect of the driven gear compare with those of the driving gear. [2 marks]
Question 3 — Electric circuits (10 marks)
(a) Which component's resistance falls when the light falling on it gets brighter? [1 mark]
A light-dependent resistor B thermistor C diode D fixed resistor
(b) A 6.0 Ω resistor and a 12 Ω resistor are connected in series with a 9.0 V battery.
(i) State the total resistance of the circuit. [1 mark]
(ii) Calculate the current in the circuit. [2 marks]
(iii) Calculate the potential difference across the 12 Ω resistor. [2 marks]
(c) The same two resistors are reconnected in parallel with the 9.0 V battery. Explain why the current from the battery is now larger than in (b). [2 marks]
(d) A lamp carries a current of 0.25 A for 2 minutes. Calculate the charge that flows through the lamp. [2 marks]
Question 4 — Core practical: investigating I–V characteristics (10 marks)
A student investigates how the current through a filament lamp varies with the potential difference across it. The results are shown.
| Potential difference (V) | 0 | 1.0 | 2.0 | 3.0 | 4.0 | 5.0 |
|---|---|---|---|---|---|---|
| Current (A) | 0 | 0.20 | 0.32 | 0.40 | 0.46 | 0.50 |
(a) Describe how the student could obtain these results. Include the equipment used and how the potential difference is changed. [3 marks]
(b) Calculate the resistance of the lamp at 1.0 V and at 5.0 V. [2 marks]
(c) Explain, in terms of the particles in the filament, why the resistance of the lamp increases as the potential difference increases. [3 marks]
(d) The lamp is replaced with a diode. Describe how the current–potential difference graph for the diode is different from the graph for the lamp. [2 marks]
Question 5 — Mains electricity and energy transfer (10 marks)
A kettle is rated at 2.8 kW. It is connected to the 230 V mains supply.
(a) Calculate the energy transferred by the kettle in 3 minutes. [2 marks]
(b) Calculate the current in the kettle. [2 marks]
(c) Fuses are available with ratings of 3 A, 5 A and 13 A. State which fuse should be fitted to the kettle's plug, and give a reason. [2 marks]
(d) The kettle has a metal case. A fault causes the live wire to touch the case. Explain how the earth wire and the fuse together protect the user. [3 marks]
(e) What colour is the insulation on the live wire in a UK mains cable? [1 mark]
A blue B green and yellow C brown D black
Question 6 — Static electricity (10 marks)
(a) A polythene rod becomes negatively charged when it is rubbed with a dry cloth. Explain how the rod becomes charged. [2 marks]
(b) Describe the electric field pattern around an isolated, positively charged sphere. [2 marks]
(c)* When an aircraft is refuelled, fuel flows quickly through a long hose from the tanker into the aircraft's tanks. Before refuelling begins, a metal cable is connected between the aircraft, the tanker and the ground.
Explain how a charge can build up during refuelling, why this is dangerous, and how the cable makes refuelling safe. [6 marks]
Question 7 — Magnetism and the motor effect (10 marks)
(a) Describe how a student could use a plotting compass to find the shape of the magnetic field around a bar magnet. [3 marks]
(b) A straight wire 0.15 m long carries a current of 3.0 A at right angles to a uniform magnetic field of magnetic flux density 0.08 T. Calculate the force on the wire. [2 marks]
(c) State two changes, either of which would reverse the direction of the force on the wire. [2 marks]
(d) Explain how the split-ring commutator keeps the coil of a simple d.c. motor turning in the same direction. [3 marks]
Question 8 — Electromagnetic induction and the National Grid (10 marks)
(a) A transformer has 50 turns on its primary coil and 1000 turns on its secondary coil. The potential difference across the primary coil is 12 V. Calculate the potential difference across the secondary coil. [2 marks]
(b) The transformer is 100% efficient. The current in the secondary coil is 0.20 A. Calculate the current in the primary coil. [2 marks]
(c)* Power stations generate electricity at about 25 000 V, but it is sent across the country through the National Grid at up to 400 000 V and supplied to homes at 230 V.
Explain why electricity is transmitted at very high potential differences, and how transformers are used in the National Grid. [6 marks]
Question 9 — Core practical: properties of water (10 marks)
(a) A student places a 50 W immersion heater in 0.50 kg of water in an insulated beaker. The heater is switched on for 10 minutes and the temperature of the water rises from 18 °C to 31 °C.
(i) Calculate the energy supplied by the heater. [2 marks]
(ii) Calculate the specific heat capacity of the water from these results. [2 marks]
(iii) The accepted value is 4200 J/kg °C. Explain why the student's value is higher than this, and suggest one improvement to the method. [2 marks]
(b) The student then heats crushed ice, starting at −10 °C, and records its temperature every 30 s. Describe and explain the shape of the temperature–time graph while the ice is melting. [2 marks]
(c) Calculate the energy needed to melt 0.20 kg of ice at 0 °C. The specific latent heat of fusion of ice is 334 000 J/kg. [2 marks]
Question 10 — Forces and matter (10 marks)
(a) In a core practical, a student hangs weights from a spring and measures its extension.
| Force (N) | 0 | 1.0 | 2.0 | 3.0 | 4.0 | 5.0 |
|---|---|---|---|---|---|---|
| Extension (cm) | 0 | 2.5 | 5.0 | 7.5 | 10.0 | 14.0 |
(i) Calculate the spring constant of the spring. [2 marks]
(ii) State between which two forces the limit of proportionality is passed. [1 mark]
(iii) Calculate the energy stored in the spring when its extension is 10.0 cm. [2 marks]
(b) A diver is 25 m below the surface of the sea. Calculate the pressure on the diver due to the water. The density of the water is 1000 kg/m³. [2 marks]
(c) Explain why an object under water experiences an upward force called upthrust. [3 marks]