levo

Electromagnetism

Magnetic flux, flux linkage and Faraday's law

  • 3 things to know
  • Papers 1, 2 and 3

Overview

Recall questions on the weber, magnetic flux linkage, Faraday's law and Lenz's law, calculating induced e.m.f., and changing the flux linkage through a search coil.

What you need to know

Answer each one before you reveal it.

Your recallNot started
Numbers

Write the equation for induced e.m.f. that combines Faraday's and Lenz's laws, and explain the significance of the negative sign.

Key term

Define one weber in terms of tesla and square metre.

Key term

Define magnetic flux linkage for a coil.

Questions from this subtopic

Each one with the model answer underneath.

  1. 1

    Define one weber in terms of tesla and square metre.

    Model answer

    One weber equals one tesla multiplied by one square metre (1 Wb = 1 T m²).

  2. 2

    Define magnetic flux linkage for a coil.

    Model answer

    Magnetic flux linkage is the product of the magnetic flux through the coil and the number of turns: flux linkage = NΦ.

  3. 3

    Calculate the flux linkage when number of turns = 910, magnetic flux = 0.0031 Wb.

    Model answer

    Flux linkage = 910 × 0.0031 = 2.82 Wb.

  4. 4

    State Faraday's law of electromagnetic induction.

    Model answer

    The magnitude of the induced e.m.f. is equal to the rate of change of magnetic flux linkage.

  5. 5

    State Lenz's law.

    Model answer

    The direction of an induced e.m.f. or current is such as to oppose the change producing it.

  6. 6

    Write the equation for induced e.m.f. that combines Faraday's and Lenz's laws, and explain the significance of the negative sign.

    Model answer

    ε = −Δ(NΦ)/Δt. The negative sign indicates that the induced e.m.f. opposes the change in flux linkage.

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.

Practical Skills in the Written Papers
The Practical Endorsement
Physical Quantities and Units
Making Measurements and Analysing Data

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.
longitudinaltransversestationary

Blank Blitz makes facts automatic

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

AForce is a vector quantity.
BDistance is a scalar quantity.
CVelocity is a vector quantity.

Build It gets the exam shape right

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

Density means mass per unit volume.
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 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.

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