What is the generator effect?

The effect in which a potential difference is induced across a conductor when it moves relative to a magnetic field or when the magnetic field around it changes.

Under what condition does an induced potential difference produce an induced current?

When the conductor forms part of a complete circuit.

A wire is held still between the poles of a magnet and nothing is induced across it. Explain why.

There is no relative movement and the magnetic field is not changing, so nothing induces a potential difference.

What does the magnetic field produced by an induced current always do?

It opposes the change that produced it, whether that change is the movement of the conductor or a change in the magnetic field.

AQA GCSE Physics 8463

Atomic Structure

Topic overview The structure of an atom Mass number, atomic number and isotopes From the plum pudding model to the nuclear model Chadwick, the neutron, and comparing the models Radioactive decay and nuclear radiation Nuclear equations Half-lives and the random nature of radioactive decay Radioactive contamination Background radiation Uses of nuclear radiation, and how half-life affects hazard Nuclear fission and nuclear fusion

Electricity

Topic overview Circuit symbols, electrical charge and current Current, resistance and potential difference Ohmic conductors, filament lamps, diodes and thermistors Light-dependent resistors, and investigating resistance Current and potential difference in series and parallel Constructing circuits, and calculating in series circuits Direct and alternating potential difference, and mains electricity Power and efficiency Appliances, and the energy transferred by electrical work Power, and the power ratings of domestic appliances The National Grid Static charge Electric fields

Energy

Topic overview Energy stores and systems Kinetic energy Elastic and gravitational potential energy Energy changes in systems Power Energy transfers in a system The main energy resources, renewable and non-renewable Environmental impact and trends in energy use

Forces

Topic overview Scalars, vectors, forces and the resultant force Gravity Work done and energy transfer Stretching, compressing, and the spring constant Linear and non-linear extension, and work done on a spring Moments, levers and gears Pressure at a surface, and the equation p = F over A Pressure in a column of liquid, upthrust and floating Atmospheric pressure Resolving forces and free body diagrams Distance, displacement and speed The speed of sound, and the distance-speed-time equation Velocity and the distance-time relationship Acceleration, deceleration and velocity-time graphs Area under a velocity-time graph, and the uniform acceleration equation Newton's First Law Newton's Second and Third Laws Stopping distance and reaction time Factors affecting braking distance Braking force, deceleration and the dangers of stopping quickly Momentum and its conservation Changes in momentum

Magnetism and Electromagnetism

Topic overview Poles of a magnet Magnetic fields around a magnet The compass, and plotting a magnetic field Electromagnetism Fleming's left-hand rule, motors and loudspeakers Induced potential The generator effect, alternators, dynamos and microphones The structure of a transformer and the turns ratio Transformer power, and using the transformer equations

Particle Model of Matter

Topic overview Density of materials Changes of state and internal energy Temperature changes in a system and specific heat capacity Changes of state and specific latent heat Particle motion in gases Pressure in gases, and increasing the pressure of a gas

Space Physics

Topic overview Our solar system, and the orbits of satellites The life cycle of a star Red-shift

Waves

Topic overview Transverse and longitudinal waves, and the wave equation Wave properties, and refraction at a boundary Reflection of waves Sound waves Ultrasound, echo sounding and seismic waves Types and uses of electromagnetic waves Radio waves, and the hazards of ultraviolet, X-rays and gamma rays Lenses Visible light Emission and absorption of infrared radiation, and black bodies

Magnetism and Electromagnetism

Induced potential

3 things to know
Paper 2

Overview

The generator effect and the two ways of inducing a potential difference, when an induced current flows and why its magnetic field opposes the change, the extra effort needed to push a magnet into a coil or turn a dynamo, the factors affecting the induced potential difference, and what reverses its direction.

What you need to know

Answer each one before you reveal it.

Your recallNot started

Key term

State the two situations that induce a potential difference across a conductor.

Key term

A magnet is pushed into a coil that is part of a complete circuit. Explain why a force resists the push.

Key term

Explain why a bicycle dynamo makes pedalling harder when it is switched on to power a bright lamp.

Questions from this subtopic

Each one with the model answer underneath.

1
What is the generator effect?
Model answer
The effect in which a potential difference is induced across a conductor when it moves relative to a magnetic field or when the magnetic field around it changes.
2
State the two situations that induce a potential difference across a conductor.
Model answer
The conductor moving relative to a magnetic field, and the magnetic field around the conductor changing.
3
Under what condition does an induced potential difference produce an induced current?
Model answer
When the conductor forms part of a complete circuit.
4
A wire is held still between the poles of a magnet and nothing is induced across it. Explain why.
Model answer
There is no relative movement and the magnetic field is not changing, so nothing induces a potential difference.
5
What does the magnetic field produced by an induced current always do?
Model answer
It opposes the change that produced it, whether that change is the movement of the conductor or a change in the magnetic field.
6
A magnet is pushed into a coil that is part of a complete circuit. Explain why a force resists the push.
Model answer
The induced current makes its own magnetic field that opposes the magnet's motion, so work has to be done to keep pushing the magnet in.

See the rest and revise

Other ways to work this

The same content, four other ways.

What is inside Levo

Six ways to work the same material.

1Closed book

2Open book

3Closed book

The 3-step method, run for you

Answer cold, learn it, then prove it stuck. Levo tracks the jump between your first attempt and your last.

Atomic Structure

Electricity

Energy

Forces

Cram a whole paper in one sitting

Sort every topic into what you know and what you do not, then drill only the weak ones.

A wave.

transverselongitudinalmechanical

Blank Blitz makes facts automatic

Rapid timed gap-fills on the terms and numbers you need to recall without thinking.

AA cloud of dust and gas in space.

BThe force of gravity pulls the material together.

CThe material is pulled together tightly enough for nuclei to fuse.

Build It gets the exam shape right

Assemble a full-mark answer from its marking points, in the order an examiner wants them.

Moon means a natural body orbiting a planet.

TrueFalse

Test It catches misconceptions

Spot the fault in a statement. The traps are the mistakes students actually make.

721941163128510

Brain Breaks between sessions

Short focus games to reset attention, so the next set lands better than the last.

Every question in Magnetism and Electromagnetism, 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.

Start revising, £5 a month See how the method works

Or £46 a year, about £3.83 a month. Cancel anytime.