Electromagnetic Induction | Edexcel GCSE Combined Science Physics, Higher tier (1SC0)
Electromagnetic Induction
- 39 questions
- 4 subtopics
- Paper 6
- Paper 6
Electromagnetic Induction is examined in Paper 6, Physics 2.
It covers factors affecting an induced potential difference, how a transformer works, the national grid, and step-up and step-down transformers and transformer power calculations.
Sample questions from Electromagnetic Induction
Answer each one closed book first, then open the answer.
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Factors affecting an induced potential difference
Describe how the direction of the induced current changes when a magnet is pulled out of a coil instead of pushed into it.
Show the answer
The induced current flows in the opposite direction. -
Factors affecting an induced potential difference
Explain why a force must be applied to push a magnet into a coil that is part of a complete circuit.
Show the answer
The induced current makes a magnetic field that repels the approaching magnet, so it must be pushed against that field. -
How a transformer works
State the purpose of the iron core in a transformer.
Show the answer
It carries the changing magnetic field from the primary coil across to the secondary coil. -
How a transformer works
State what a transformer does to an alternating voltage.
Show the answer
It changes the size of the voltage, making it either larger or smaller. -
The national grid, and step-up and step-down transformers
State the effect of transferring electrical energy at high voltage on the efficiency of the transmission network.
Show the answer
The efficiency is higher, because less of the energy is wasted heating the cables. -
The national grid, and step-up and step-down transformers
Explain why a step-up transformer is used as electricity leaves a power station.
Show the answer
It raises the voltage so the current in the cables is small and far less energy is wasted as heat. -
Transformer power calculations
A transformer takes 2.0 A from a 230 V supply and gives an output of 23 V. Calculate the output current.
Show the answer
Input power = 230 × 2.0 = 460 W, so output current = 460 ÷ 23 = 20 A. -
Transformer power calculations
A transformer runs a 6.0 V lamp from a 240 V supply and draws 0.50 A from that supply. Calculate the current in the lamp.
Show the answer
Input power = 240 × 0.50 = 120 W, so the lamp current = 120 ÷ 6.0 = 20 A.
The 4 subtopics
One subtopic is one session. Work down the list.
| Subtopic | What it covers | Questions |
|---|---|---|
| Factors affecting an induced potential difference | The speed, magnet strength and number of turns that set the induced potential difference, reversing the movement or the pole, and why the induced field opposes the change that made it. | 8 |
| How a transformer works | The construction of a transformer, how an alternating current in the primary coil induces a potential difference in the secondary, why direct current gives no output, the soft iron core, and what step-up and step-down transformers do. | 10 |
| The national grid, and step-up and step-down transformers | Transmitting electrical energy at high voltage and low current to cut heating losses in cables, the national grid and its thick cables, where and why step-up and step-down transformers are used, the 230 V mains, and why the grid uses alternating current. | 13 |
| Transformer power calculations | The power equation for a 100% efficient transformer, calculating an output current, an output voltage or a primary current, and why stepping the voltage up lowers the current. | 8 |
How the guide is worked
Answering a question from memory stores it far better than reading the answer again. The guide runs that as a fixed procedure on one subtopic at a time, about twenty minutes a session.
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Step 1 · Closed book
Cover the answers. Work through one subtopic and write down what you can. Leave blanks where you have nothing.
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Step 2 · Open book
Go back to the top. Read each printed answer and write it out in full, including the ones you had right.
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Step 3 · Closed book again
Same questions, same order, from memory. The gap between pass one and pass three is the session result.
Read the full method, the return schedule and the research behind it.
Nearby topics
Edexcel GCSE Combined Science Physics, Higher tier Active Recall Guide
Every topic, not just this one. 1,449 questions with their answers.