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, diagram 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 1 content, topics 1 to 7: key concepts of physics; motion and forces; conservation of energy; waves; light and the electromagnetic spectrum; radioactivity; and astronomy.
- Take the gravitational field strength g = 10 N/kg.
- Equations you may need that are on the Edexcel physics equations list: (final velocity)² − (initial velocity)² = 2 × acceleration × distance; force = change in momentum ÷ time.
Paper
Question 1 — Describing motion (10 marks)
(a) Which of these is a vector quantity? [1 mark]
A speed B distance C displacement D mass
(b) A runner completes one lap of a 400 m track in 50 s. Calculate the runner's average speed. [2 marks]
(c) A car travels at 72 km/h. Convert this speed to m/s. [1 mark]
(d) A train starts from rest and accelerates uniformly to 24 m/s in 40 s. It then travels at a constant 24 m/s for 60 s. Finally, it decelerates uniformly and comes to rest after a further 30 s.
(i) Calculate the acceleration of the train in the first 40 s. [2 marks]
(ii) Use the area under the velocity–time graph of this journey to calculate the total distance travelled. [3 marks]
(e) State what the gradient of a distance–time graph represents. [1 mark]
Question 2 — Core practical: investigating acceleration (10 marks)
A student investigates how the mass of a trolley affects its acceleration when the force on it is kept constant. The trolley is pulled along a level runway by a string that passes over a pulley to a hanging mass. Two light gates are placed on the runway.
(a) (i) State the independent variable in this investigation. [1 mark]
(ii) State how the student keeps the accelerating force constant. [1 mark]
(b) The student's results are shown.
| Mass of trolley (kg) | 0.50 | 0.75 | 1.00 | 1.50 |
|---|---|---|---|---|
| Acceleration (m/s²) | 1.20 | 0.80 | 0.60 | 0.40 |
Describe the relationship between the mass of the trolley and its acceleration. Use the data to support your answer. [2 marks]
(c) Use the results to calculate the accelerating force. [2 marks]
(d) Give one advantage of using light gates rather than a stopwatch. [1 mark]
(e) In one run, the trolley passes the first light gate at 0.30 m/s and the second at 0.90 m/s. The light gates are 0.60 m apart.
Calculate the acceleration of the trolley. [3 marks]
Question 3 — Forces and momentum (10 marks)
(a) State Newton's third law of motion. [1 mark]
(b) The Moon orbits the Earth at a constant speed. Explain why the Moon is accelerating, and state the direction of the resultant force on it. [2 marks]
(c) A rifle of mass 4.0 kg is at rest. It fires a bullet of mass 0.010 kg at a velocity of 400 m/s.
Calculate the velocity at which the rifle recoils. [3 marks]
(d) A goalkeeper catches a 0.45 kg football travelling at 20 m/s and brings it to rest in 0.090 s.
Calculate the average force on the ball. [2 marks]
(e) Explain why the goalkeeper pulls their hands back while catching the ball. [2 marks]
Question 4 — Stopping and weight (10 marks)
(a) The gravitational field strength on Mars is 3.7 N/kg. Calculate the weight of an 80 kg astronaut on Mars. [2 marks]
(b) A driver travelling at 18 m/s has a reaction time of 0.70 s. Calculate the thinking distance. [2 marks]
(c) The car and driver have a total mass of 1200 kg. When the brakes are applied, the braking force is 6000 N.
Calculate the braking distance from 18 m/s. [3 marks]
(d) Explain why large decelerations in a collision are dangerous for the people in a car. [2 marks]
(e) Give one factor, other than speed, that increases the braking distance of a car. [1 mark]
Question 5 — Conservation of energy (10 marks)
(a) A tennis ball of mass 0.060 kg is dropped from a height of 2.5 m.
(i) Calculate the gravitational potential energy lost by the ball as it falls to the ground. [2 marks]
(ii) Calculate the speed of the ball just before it hits the ground. Ignore air resistance. [3 marks]
(b) The ball bounces back up to a height of 1.6 m. Calculate the efficiency of the bounce. [2 marks]
(c) Explain how cavity wall insulation reduces the rate of energy transfer from a house. [2 marks]
(d) Give one disadvantage of generating electricity from fossil fuels. [1 mark]
Question 6 — Waves (10 marks)
(a) A sound wave in air has a wavelength of 0.85 m. The speed of sound in air is 340 m/s. Calculate the frequency of the sound. [2 marks]
(b) In a core practical, a student strikes the end of a metal rod 2.0 m long with a hammer. A frequency app on a phone held near the rod shows a peak frequency of 1250 Hz. The wavelength of this sound in the rod is twice the length of the rod.
Calculate the speed of sound in the metal. [3 marks]
(c) A ship sends a pulse of ultrasound straight down to the seabed. The echo returns 0.40 s later. The speed of sound in sea water is 1500 m/s.
Calculate the depth of the water. [2 marks]
(d) After an earthquake, S-waves are not detected on the opposite side of the Earth. Explain what this shows about the structure of the Earth. [2 marks]
(e) Give the range of frequencies that can be heard by humans. [1 mark]
Question 7 — Light and the electromagnetic spectrum (10 marks)
(a) In a core practical, a student investigates refraction by shining a ray of light into a rectangular glass block.
(i) Describe how the student can measure the angle of incidence and the angle of refraction. [2 marks]
(ii) Explain why the ray bends towards the normal as it enters the glass. [1 mark]
(b) A white shirt is looked at through a green filter. Explain why the shirt appears green. [2 marks]
(c) Give one use of gamma rays and explain why gamma rays are suitable for this use. [2 marks]
(d) A hot object stays at a constant temperature. What does this show about the radiation it absorbs and emits? [1 mark]
(e) Explain how the radiation emitted by an object changes as its temperature increases. [2 marks]
Question 8 — Radioactivity (10 marks)
(a) Strontium-90 (atomic number 38) decays by beta-minus emission to form yttrium (Y).
Write the balanced nuclear equation for this decay. [2 marks]
(b) State what happens to the mass number of a nucleus when it emits a neutron. [1 mark]
(c) Describe what happens in the nucleus during beta-plus (positron) decay. [1 mark]
(d) Iodine-131 has a half-life of 8 days. A sample has an activity of 2.4 MBq. Calculate its activity after 32 days. [2 marks]
(e) PET scanners use radioactive isotopes with very short half-lives. Explain why these isotopes must be produced close to the hospital, and why a short half-life is an advantage for the patient. [2 marks]
(f) (i) Give one natural source of background radiation. [1 mark]
(ii) Explain why a student measuring the count rate from a source subtracts the background count rate. [1 mark]
Question 9 — Fission and fusion (10 marks)
(a)* Describe how a chain reaction is produced and controlled in a nuclear reactor, and how the energy released is used to generate electricity. [6 marks]
(b) Explain why nuclear fusion needs very high temperatures and pressures. [2 marks]
(c) Give one reason why nuclear fusion is not yet used to generate electricity commercially. [1 mark]
(d) Apart from energy, state what is produced when a nucleus of uranium-235 undergoes fission. [1 mark]
Question 10 — Astronomy (10 marks)
(a)* Explain how observations of red-shift and of the cosmic microwave background (CMB) radiation support the Big Bang theory rather than the Steady State theory. [6 marks]
(b) Put these stages in the life cycle of a star like the Sun into the correct order: main sequence star, nebula, white dwarf, red giant, protostar. [1 mark]
(c) Explain why a main sequence star stays a stable size for a long time. [2 marks]
(d) Explain why a satellite in a lower circular orbit must travel at a higher speed than one in a higher orbit. [1 mark]