Magnetic Flux

Magnetic flux $\phi$ through a plane surface is the product of the magnetic flux density normal to the surface BN and the area A of the surface.

  • S.I. unit for $\phi$ is weber(Wb) or T m2
  • Base Units for Wb: kg m2 s -1 C -1

$\phi = AB_{N} \, = AB \, cos \, \theta$, where

$\theta$ is the angle between the B-field and the normal to the area A.

The weber is defined as the magnetic flux through a surface if a magnetic field of flux density 1 T exists perpendicularly to an area of 1 m2.

When a coil of N turns is placed instead,

Magnetic Flux Linkage $\Phi$ is defined as the product of the number of turns N of the coil and the magnetic flux $\phi$ linking each turn.

$\Phi = N \phi \, = NAB_{N} \, = NAB \, cos \, \theta$, where

  • A is area of coil
  • $\theta$ is the orientation of the coil with respect to the direction of B

The magnetic flux linkage through a coil depends on:

  • number of turns in the coil
  • area of the coil
  • external magnetic flux density
  • the orientation of the coil with respect to the direction of B

Back To Electromagnetic Induction (A Level Physics)

Back To A Level Physics Topic List

Mini Physics

As the Administrator of Mini Physics, I possess a BSc. (Hons) in Physics. I am committed to ensuring the accuracy and quality of the content on this site. If you encounter any inaccuracies or have suggestions for enhancements, I encourage you to contact us. Your support and feedback are invaluable to us. If you appreciate the resources available on this site, kindly consider recommending Mini Physics to your friends. Together, we can foster a community passionate about Physics and continuous learning.

Leave a Comment

This site uses Akismet to reduce spam. Learn how your comment data is processed.