Pearson Edexcel International GCSE in Physics · 4PH1 · Free · no account needed
Orbits — exam questions
11 original Incandio exam-style questions on orbits, 25 marks, about 25 minutes of writing. Each one carries the command word, the tariff and the specification statement it assesses, exactly as a paper presents them. This is an original Incandio practice question, written to reflect the structure and demands of the qualification. It is not an official Pearson Edexcel past-paper question.
This is the practice set for Orbits — the lesson that teaches it. Read the lesson first if the idea is new; come here when you want to find out whether you can turn it into marks. Completely free, no account needed to read.
What these questions ask of you
6 command words run through this set, and on Pearson Edexcel International GCSE Physics each one means something precise. Answering the wrong command is the commonest way a candidate who understands the lesson still loses the mark.
- Which (1 mark)
- one option chosen from the set given
- Name (1 mark)
- the correct quantity, unit or component
- Give (1–2 marks)
- a short factual answer
- Explain (2–4 marks)
- the physics that causes it, set out as a line of reasoning Misread as: describing the change without giving the physical reason for it
- Calculate (1–5 marks)
- select the equation, substitute, evaluate — and state the unit Misread as: giving a bare number with no equation and no unit
- Suggest (1–3 marks)
- a plausible answer applying taught physics to an unfamiliar arrangement
Assessed on Paper 1 (4PH1/1P) and Paper 2 (4PH1/2P), against AO1, AO2, AO3.
Where these sit in the specification
Pearson Edexcel International GCSE Physics (4PH1) — statements 8.4 · 8.5 · 8.6. Incandio is aligned to this specification; it is not published by, endorsed by or affiliated with Pearson, and it reproduces none of Pearson's wording.
The 11 questions
Answer them on paper, then open the lesson's exam practice to have them marked. The mark scheme, the accepted and rejected answers and the annotated model answer are in Incandio and are not printed here — an answer beside its question is not practice.
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An astronomy club tabulated the four largest moons of Jupiter, listing how far each one orbits from the planet's centre and how long each takes to go round once.
Table 1 — the four largest moons of Jupiter Moon Orbital radius / m Orbital period / days Io 4.2 × 10⁸ 1.8 Europa 6.7 × 10⁸ 3.6 Ganymede 1.1 × 10⁹ 7.2 Callisto 1.9 × 10⁹ 16.7 (a)
(1)Give
Give the orbital period of Ganymede in days, using Table 1.
An astronomy club tabulated the four largest moons of Jupiter, listing how far each one orbits from the planet's centre and how long each takes to go round once.
Table 1 — the four largest moons of Jupiter Moon Orbital radius / m Orbital period / days Io 4.2 × 10⁸ 1.8 Europa 6.7 × 10⁸ 3.6 Ganymede 1.1 × 10⁹ 7.2 Callisto 1.9 × 10⁹ 16.7 orbital period of Ganymede = ............................
(b)
(4)Calculate
Calculate the orbital speed of Io in metres per second, using Table 1.
An astronomy club tabulated the four largest moons of Jupiter, listing how far each one orbits from the planet's centre and how long each takes to go round once.
Table 1 — the four largest moons of Jupiter Moon Orbital radius / m Orbital period / days Io 4.2 × 10⁸ 1.8 Europa 6.7 × 10⁸ 3.6 Ganymede 1.1 × 10⁹ 7.2 Callisto 1.9 × 10⁹ 16.7 orbital speed of Io = ............................ m/s
(c)
(3)Explain
Explain the pattern Table 1 shows between orbital radius and orbital period.
An astronomy club tabulated the four largest moons of Jupiter, listing how far each one orbits from the planet's centre and how long each takes to go round once.
Table 1 — the four largest moons of Jupiter Moon Orbital radius / m Orbital period / days Io 4.2 × 10⁸ 1.8 Europa 6.7 × 10⁸ 3.6 Ganymede 1.1 × 10⁹ 7.2 Callisto 1.9 × 10⁹ 16.7 (Total for Question 1 = 8 marks)
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(1)Which
Which direction does the gravitational force on an orbiting satellite act in?
Direction A along the direction it is moving B opposite to the direction it is moving C towards the centre of the orbit D away from the centre of the orbit (Total for Question 2 = 1 mark)
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(1)Name
Name the force that keeps a planet in orbit around the Sun.
(Total for Question 3 = 1 mark)
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(1)Give
Give one way in which a comet's orbit differs from a planet's orbit.
(Total for Question 4 = 1 mark)
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(3)Explain
Explain why a satellite in a circular orbit is accelerating even though its speed is constant.
(Total for Question 5 = 3 marks)
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(3)Calculate
A satellite orbits at a radius of 7.0 × 10⁶ m with a period of 6000 s. Calculate its orbital speed.
orbital speed = ............................ m/s
(Total for Question 6 = 3 marks)
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(3)Explain
Explain why a comet travels much faster when it is close to the Sun than when it is far away.
(Total for Question 7 = 3 marks)
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(3)Suggest
Suggest why a satellite in this orbit stays above the same point on the equator.
A communications satellite — A television satellite is placed in a circular orbit of radius 4.2 × 10⁷ m, directly above the equator and travelling in the same direction as the Earth's rotation. Its orbital period works out at exactly 24 hours. A dish on the ground can be bolted in one position and never needs moving.
(Total for Question 8 = 3 marks)
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(2)Explain
Explain why a satellite in a low orbit completes an orbit in a shorter time than one much further out.
(Total for Question 9 = 2 marks)
Have them marked, then defend the answer
Practice tells you the mark; teaching it back tells you whether you understand it. On Incandio a topic counts as mastered only once you have taught it and defended it.
- Mark these questions — 11 questions, marked on Incandio against the authored scheme, with the mistake you actually made named.
- Teach it — explain orbits to Ember, an AI pupil who does not have it yet and asks the awkward question.
- Defend it — argue it against Johannes Kepler over three rounds, marked against descriptors you can read first.
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Back to the lesson
- Orbits — Why anything in orbit is falling, why comets speed up as they arrive, and how to find an orbital speed.
- All of Incandio Physics · Incandio Exam Practice