Total marks: 90 · Duration: 105 minutes · Tier: Higher
Instructions to candidates
- Use black ink. You may use an HB pencil for graphs and diagrams.
- Answer all the questions.
- In calculations, show your working and give the unit of your answer.
- You may use a scientific or graphical calculator.
- Section A: for each question, choose one answer, A, B, C or D.
- Where a question describes a circuit, graph or apparatus in words, you may find it helpful to sketch it.
Information
- The total mark for this paper is 90. Section A is worth 15 marks and Section B is worth 75 marks.
- The marks for each question are shown in brackets.
- Quality of extended response will be assessed in questions marked with an asterisk (*).
- This paper covers OCR GCSE (9–1) Gateway Physics A Higher Paper 1 content, topics P1 to P4: matter; forces; electricity; and magnetism and magnetic fields.
- Take the gravitational field strength g = 10 N/kg.
- Equations you may need that are on the OCR physics equation sheet: (final velocity)² − (initial velocity)² = 2 × acceleration × distance; energy transferred in stretching = ½ × spring constant × (extension)²; thermal energy for a change of state = mass × specific latent heat; change in thermal energy = mass × specific heat capacity × change in temperature; potential difference across primary coil × number of turns in secondary coil = potential difference across secondary coil × number of turns in primary coil; force on a conductor = magnetic flux density × current × length.
Paper
Section A — Multiple choice (15 marks)
1. What is the unit of density? [1 mark]
A kg B kg/m C kg/m³ D m³/kg
2. Which change of state is sublimation? [1 mark]
A solid to gas B gas to liquid C liquid to gas D solid to liquid
3. Which statement describes the plum pudding model of the atom? [1 mark]
A electrons orbit a tiny positive nucleus in fixed shells B the atom is a solid sphere that cannot be divided C most of the mass is concentrated in a small nucleus D negative electrons are embedded in a sphere of positive charge
4. A sealed container of gas is heated. Its volume does not change. What happens to the pressure of the gas? [1 mark]
A it decreases B it increases C it stays the same D it falls to zero
5. What is the unit of momentum? [1 mark]
A kg m/s B kg m/s² C N/s D J/s
6. What does the gradient of a distance–time graph represent? [1 mark]
A acceleration B distance travelled C speed D resultant force
7. A car of mass 1000 kg accelerates at 2.0 m/s². What is the resultant force on the car? [1 mark]
A 500 N B 2000 N C 1000 N D 20 000 N
8. A force of 4.0 N stretches a spring by 0.050 m. What is the spring constant? [1 mark]
A 0.2 N/m B 8.0 N/m C 20 N/m D 80 N/m
9. A force of 20 N acts at right angles to a spanner, 0.30 m from the pivot. What is the moment of the force? [1 mark]
A 0.015 N m B 67 N m C 6.0 N m D 600 N m
10. A current of 2.0 A flows for 30 s. How much charge flows? [1 mark]
A 60 C B 15 C C 0.067 C D 32 C
11. Two 6.0 Ω resistors are connected in parallel. What is their combined resistance? [1 mark]
A 12 Ω B 3.0 Ω C 6.0 Ω D 36 Ω
12. A polythene rod is rubbed with a cloth and becomes negatively charged. Why? [1 mark]
A protons moved from the rod to the cloth B protons moved from the cloth to the rod C electrons moved from the rod to the cloth D electrons moved from the cloth to the rod
13. Which change increases the strength of the magnetic field of a solenoid? [1 mark]
A removing the iron core B reducing the current C increasing the number of turns D reversing the current
14. In Fleming's left-hand rule, what does the thumb represent? [1 mark]
A the force (motion) B the current C the magnetic field D the potential difference
15. A step-down transformer has 1000 turns on its primary coil and 50 turns on its secondary coil. The primary coil is connected to 230 V. What is the potential difference across the secondary coil? [1 mark]
A 4600 V B 11.5 V C 4.6 V D 230 V
Section B (75 marks)
Question 16 — Matter (11 marks)
(a) A cube of aluminium has sides of 3.0 cm and a mass of 72.9 g. Calculate the density of aluminium in kg/m³. [3 marks]
(b) Calculate the energy needed to melt 0.50 kg of ice at 0 °C. The specific latent heat of fusion of ice is 334 000 J/kg. [2 marks]
(c) Calculate the energy needed to warm the 0.50 kg of water from 0 °C to 20 °C. The specific heat capacity of water is 4200 J/kg °C. [2 marks]
(d) A gas occupies 120 cm³ at a pressure of 100 kPa. It is compressed slowly to 40 cm³ at constant temperature. Calculate the new pressure. [2 marks]
(e) Explain, in terms of particles, why compressing the gas increases its pressure. [2 marks]
Question 17 — The atom and static electricity (8 marks)
(a) Describe how the model of the atom changed when the electron was discovered. [2 marks]
(b) The radius of an atom is about 1 × 10⁻¹⁰ m. The radius of its nucleus is about 1 × 10⁻¹⁴ m. How many times larger is the atom than the nucleus? [1 mark]
(c) A balloon is rubbed on a student's hair. The balloon becomes negatively charged. Explain what happens to the charge on the balloon and on the hair. [2 marks]
(d) Describe the shape and direction of the electric field around an isolated positively charged sphere. [1 mark]
(e) When an aircraft is refuelled, the fuel pipe is connected to earth. Explain why. [2 marks]
Question 18 — Motion and forces (12 marks)
(a) A sprinter of mass 70 kg accelerates uniformly from rest to 10 m/s in 4.0 s.
(i) Calculate the acceleration of the sprinter. [2 marks]
(ii) Calculate the distance the sprinter travels in the 4.0 s. [1 mark]
(iii) Calculate the resultant force on the sprinter. [2 marks]
(b) A snooker ball of mass 0.17 kg moving at 2.0 m/s hits a stationary ball of the same mass head-on. The first ball stops. Calculate the velocity of the second ball just after the collision. [2 marks]
(c) A crane lifts a 500 kg load through a height of 12 m in 20 s.
(i) Calculate the work done on the load. [2 marks]
(ii) Calculate the useful power output of the crane. [1 mark]
(d) Passengers standing on a bus lurch forwards when the bus brakes suddenly. Explain why. [2 marks]
Question 19 — Practical: force and extension (10 marks)
A student hangs a spring from a clamp stand and adds weights. The student measures the extension for each force.
| Force (N) | 0 | 2.0 | 4.0 | 6.0 | 8.0 | 10.0 |
|---|---|---|---|---|---|---|
| Extension (cm) | 0 | 3.0 | 6.0 | 9.0 | 12.0 | 16.5 |
(a) Describe how the student can measure the extension accurately. [2 marks]
(b) Calculate the spring constant of the spring. [2 marks]
(c) State the force above which the spring no longer obeys Hooke's law. [1 mark]
(d) Calculate the energy stored in the spring when the force is 6.0 N. [2 marks]
(e) After removing the weights, the student checks whether the spring has returned to its original length. Explain why. [1 mark]
(f) Give one safety precaution the student should take. [1 mark]
(g) The student also records the extension while removing the weights one at a time. Suggest why. [1 mark]
Question 20 — Pressure and moments (8 marks)
(a) A box with a weight of 600 N rests on the floor. The area of its base is 0.20 m². Calculate the pressure it exerts on the floor. [2 marks]
(b) Calculate the pressure due to the water at a depth of 4.0 m in a swimming pool. The density of water is 1000 kg/m³. [2 marks]
(c) Explain why an object submerged in water experiences an upthrust. [2 marks]
(d) A small gear wheel drives a larger gear wheel. Explain why the larger gear wheel produces a larger moment. [2 marks]
Question 21 — Electric circuits (14 marks)
(a)* A student wants to find out how the resistance of a thermistor changes with temperature.
Describe a method the student could use. In your answer, include the measurements needed, how resistance is calculated, and the result the student should expect. [6 marks]
(b) A 4.0 Ω resistor and a resistor R are connected in series to a 12 V supply. The current in the circuit is 0.80 A.
Calculate the resistance of R. [3 marks]
(c) Calculate the power transferred in the 4.0 Ω resistor. [2 marks]
(d) Calculate the energy transferred by the supply in 5.0 minutes. [2 marks]
(e) State what is meant by an electric current. [1 mark]
Question 22 — Electromagnetism (12 marks)
(a)* Explain how a simple a.c. generator produces an alternating potential difference. Describe two ways of increasing the peak potential difference it produces. [6 marks]
(b) A wire of length 0.20 m carries a current of 1.5 A at right angles to a magnetic field of flux density 0.050 T. Calculate the force on the wire. [2 marks]
(c) A transformer has 500 turns on its primary coil and 2500 turns on its secondary coil. The primary coil is connected to a 12 V a.c. supply.
(i) Calculate the potential difference across the secondary coil. [2 marks]
(ii) Explain why a transformer does not work with a steady d.c. supply. [2 marks]