Grade 11 physics
Self-Induction, Inductance and Magnetic Field Energy
A changing current changes its magnetic flux and induces an emf that opposes the change, giving circuits inertia-like transient behaviour.
1. Core ideas and learning goals
- Self-induced emf follows Lenz rule and opposes the change of current that produces it.
- Inductance L measures flux linkage per current for a linear inductor and is measured in henries.
- The magnitude of self-induced emf grows with inductance and with the rate of current change.
- An inductor stores magnetic-field energy W = LI^2/2 in the linear model.
- Current through an ideal inductor cannot jump instantaneously; resistance controls the transient time scale in an RL circuit.
2. Physical model
A changing current changes its magnetic flux and induces an emf that opposes the change, giving circuits inertia-like transient behaviour.
A changing current changes its magnetic flux and induces an emf that opposes the change, giving circuits inertia-like transient behaviour. The model links observable changes with measurable physical quantities and conservation laws.
Before applying a relation, specify the reference frame, system boundary, initial state and approximations. The conclusion is valid only while those conditions are satisfied.