Electromagnetic Induction Lab
Discover how changing magnetic flux induces voltage in a coil. Move a magnet through a solenoid, spin a generator coil in a magnetic field, and see Faraday's law and Lenz's law play out with animated visualizations and real-time EMF graphs.
Guided Experiment: Faraday's Law — Generator Mode
If you increase the angular velocity of the rotating coil, how do you predict the peak EMF will change?
Write your hypothesis in the Lab Report panel, then click Next.
Controls
Results
Induced EMF vs Magnet Position
Data Table
(0 rows)| # | Trial | Mode | Turns (N) | B(T) | A(m²) | Peak EMF(V) | Frequency(Hz) |
|---|
Reference Guide
Faraday's Law
A changing magnetic flux through a coil induces an electromotive force (EMF) proportional to the rate of change.
Where N is the number of turns and Φ is the magnetic flux through one loop. The negative sign reflects Lenz's law. A faster change in flux or more turns produces a larger EMF.
Magnetic Flux
Magnetic flux measures how much of the magnetic field passes through the coil area.
Where B is field strength in Tesla, A is the coil area in m², and θ is the angle between the field direction and the coil's normal vector. Flux is maximum when field is perpendicular to the coil face (θ = 0).
Lenz's Law
The induced current flows in a direction that opposes the change in magnetic flux that caused it. This is a consequence of energy conservation.
When a north pole approaches the coil, the induced current creates a north pole facing it (repulsion). When the magnet retreats, the induced current creates a south pole (attraction). The magnet always experiences a force opposing its motion.
AC Generators
When a coil rotates in a uniform magnetic field, the induced EMF is sinusoidal. The peak EMF depends on angular velocity.
Where ω is the angular velocity in rad/s. The peak EMF is NBAω — doubling the rotation speed doubles the output voltage. This is the principle behind power station generators and alternators.