PhysicsChapter 10: Electromagnetism
Faraday's Law
Introduction
Faraday's law of electromagnetic induction states that the magnitude of induced e.m.f. is proportional to the rate of change of magnetic flux linkage. Mathematically: |ε| = N |ΔΦ/Δt| or in differential form: ε = -N dΦ/dt The negative sign represents the direction described by Lenz's law.
Definition
Meaning
A faster flux change produces a larger induced e.m.f. Therefore induced e.m.f. can be increased by: moving magnet faster; using stronger field; increasing coil turns; changing flux more rapidly.
Example
If flux through a 100-turn coil changes by: `0.02 Wb` in: `0.10 s` then: `|ε| = 100 × 0.020.10` `= 20 V`
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