ELECTRICITY & MAGNETISM · LAB 29

Electromagnetic induction

Move a magnet through a coil and watch changing magnetic flux generate voltage, current and electrical power.

INDUCED CURRENTZERO

Drag the magnet horizontally. Position alone does not induce voltage—magnetic flux must change.

External fieldInduced fieldPositive currentNegative current

MAGNET / VELOCITY−0.45 m

+0.40 m/s

FIELD / FLUX—

—

RATE OF CHANGE—

dΦ/dt

INDUCED EMF—

current —

POWER / ENERGY—

energy —

WHAT TO NOTICE

Change creates the voltage

A stationary magnet can produce strong flux but no induced EMF. Move it, strengthen it or rotate the coil and the flux changes. The induced current produces its own field opposing that change—Lenz’s law and conservation of energy in action.

Φ = BA cos θε = −N dΦ/dtI = ε / R

Educational dipole-field approximation. Near-field values are limited for numerical stability and are not engineering-grade predictions.