Physics › Equations › Magnetic fields

Magnetic fields equations

The 14 equations the magnetic fields notes display, each with a link to the lesson that states it. Of the 14, the data booklet prints 10, 1 is yours to memorise and 3 carry no badge either way.

Year 13 · 6 lessons with equations.

The marks refer to the AQA 7408 data booklet. An equation it prints is marked as such, and one it leaves out is marked to learn. An equation with no mark has not been checked against that booklet, and some of these belong to the Edexcel, OCR or CIE specification rather than AQA’s, so check them against your own board’s data or formula booklet.

6 lessons

Magnetic flux density and the force on a wire

F = BIl

IN THE AQA DATA BOOKLET

F = BIl \sin\theta

Force on a moving charge

F = BQv

IN THE AQA DATA BOOKLET

F = BQv \sin\theta

r = \frac{mv}{BQ}

NOT IN THE AQA DATA BOOKLET: LEARN IT

v perpendicular to B; non-relativistic, so p = mv.

V_{H} = \frac{BI}{ntq}

Magnetic flux and flux linkage

Φ = BA

IN THE AQA DATA BOOKLET

B uniform and along the normal to the area A.

NΦ = BAN\cosθ

IN THE AQA DATA BOOKLET

Electromagnetic induction: Faraday and Lenz

ε = N\frac{\DeltaΦ}{\Delta t}

IN THE AQA DATA BOOKLET

ε = BANω\sinω t

IN THE AQA DATA BOOKLET

Alternating currents

I_{rms} = \frac{I_{0}}{\sqrt{2}}

IN THE AQA DATA BOOKLET

V_{rms} = \frac{V_{0}}{\sqrt{2}}

IN THE AQA DATA BOOKLET

Transformers

\frac{N_{s}}{N_{p}} = \frac{V_{s}}{V_{p}}

IN THE AQA DATA BOOKLET

\mathrm{efficiency} = \frac{I_{s}V_{s}}{I_{p}V_{p}}

IN THE AQA DATA BOOKLET

Every equation in the library is indexed by unit on the equation index, and the magnetic fields notes are where these equations are derived and used. The one the booklet leaves out is on the equations to memorise, alongside the rest of the course.

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