Magnetic flux

Definition

Magnetic flux is the measure of the quantity of magnetism, taking into account the strength and extent of a magnetic field. It is calculated as the product of the magnetic field and the area through which it passes, perpendicular to the field.

5 Must Know Facts For Your Next Test

1. Magnetic flux is denoted by the symbol $\Phi_B$ and measured in Weber (Wb).
2. The formula for magnetic flux is $\Phi_B = B \cdot A \cdot \cos(\theta)$, where $B$ is the magnetic field strength, $A$ is the area, and $\theta$ is the angle between the field and normal to the surface.
3. When magnetic flux through a circuit changes, it induces an electromotive force (emf) according to Faraday's Law.
4. Lenz's Law states that the direction of induced emf opposes the change in magnetic flux.
5. Magnetic flux linkage refers to $N \cdot \Phi_B$, where $N$ is the number of turns in a coil.

Review Questions

• What units are used to measure magnetic flux?
• How does changing the angle between a magnetic field and a surface affect magnetic flux?
• State Faraday's Law in relation to changing magnetic flux.

Related terms

Electromotive Force (emf): A voltage generated by an energy source such as a battery or by changing magnetic fields.

Faraday's Law: $emf = -N \frac{d\Phi_B}{dt}$; indicates that a change in magnetic flux induces an emf.

Lenz's Law: The direction of induced emf opposes the change in magnetic flux causing it.