Edexcel A-Level Physics 9PH0
Working as a Physicist
Mechanics
Electric Circuits
Materials
Waves and Particle Nature of Light
Further Mechanics
Electric and Magnetic Fields
Nuclear and Particle Physics
Thermodynamics
Space
Nuclear Radiation
Gravitational Fields
Oscillations
Electric and Magnetic Fields
The conditions for inducing an e.m.f.
- 3 things to know
- Papers 1 and 3
Overview
Recall questions on what must change for an e.m.f. to be induced, the three factors that set its size, why a steady current induces nothing, and the effect of an iron core.
What you need to know
Answer each one before you reveal it.
Why is no e.m.f. induced while a magnet is held stationary inside a coil?
Why does adding a soft iron core increase the e.m.f. induced in a linked coil?
Questions from this subtopic
Each one with the model answer underneath.
- 1
What condition is necessary for an e.m.f. to be induced in a coil?
Model answer
The flux linkage through the coil must be changing.
- 2
Which three factors affect the size of the e.m.f. induced when a permanent magnet is moved into a coil?
Model answer
The speed of the relative motion, the strength of the magnet and the number of turns on the coil.
- 3
Why is no e.m.f. induced while a magnet is held stationary inside a coil?
Model answer
Because the flux linkage is constant, so its rate of change is zero.
- 4
What happens to the induced e.m.f. if the magnet is pulled out of the coil instead of being pushed in?
Model answer
The e.m.f. is induced in the opposite direction, because the flux linkage is now decreasing rather than increasing.
- 5
Why is a larger e.m.f. induced when a magnet is moved into a coil more quickly?
Model answer
Because the same change of flux linkage occurs in a shorter time, giving a greater rate of change of flux linkage.
- 6
Which three factors affect the e.m.f. induced in a coil when the current in a second coil linked to it changes?
Model answer
The rate at which the current in the first coil changes, the number of turns on each coil and whether a soft iron core links the two coils.
Other ways to work this
The same content, four other ways.
What is inside Levo
Six ways to work the same material.
Every question in Electric and Magnetic Fields, on a schedule.
Attempt a question from memory, write the correct version, then attempt it again. Levo records the jump between your first attempt and your last, and brings each question back on the day you are due to forget it.
Or £46 a year, about £3.83 a month. Cancel anytime.