Electromagnetic Induction Simulation for A-Level Physics

Use this free A-Level Physics electromagnetic induction simulation to explore Faraday’s law, Lenz’s law, magnetic flux, flux linkage and induced emf. The interactive models include a moving magnet and coil, a rotating-coil AC generator, motional emf from a conducting rod moving through a magnetic field, and an investigation mode for testing how emf depends on field strength, number of turns, coil area and angular speed.

Faraday’s law: changing flux linkage produces emf

Magnetic flux through a flat coil is Φ = BA cos θ, where θ is the angle between the field and the normal to the coil. Flux linkage is NΦ. Faraday’s law gives ε = −d(NΦ)/dt: a faster change of flux linkage produces a larger induced emf. A large constant flux linkage alone produces no emf.

Lenz’s law and conservation of energy

The induced effect opposes the change that causes it. It does not always oppose the magnetic field itself. Compare a magnet approaching and leaving a coil, then reverse its pole. If a conducting circuit is closed, the induced current transfers energy; work must be done to maintain the motion.

Predict, measure and calculate

If flux linkage changes by 0.012 Wb in 0.040 s, the magnitude of the average induced emf is 0.30 V. Determine its direction separately using Lenz’s law. In the rotating-coil model, compare flux linkage and emf: flux linkage is greatest when its rate of change is zero, so emf is then zero. Emf is greatest when flux linkage passes through zero most rapidly.

Test one variable at a time and explain your graphs using the rate of change, rather than simply saying “more flux”. Then practise A-Level fields and induction questions.

Designed for A-Level Physics students across the UK, the simulation links equations to the physical behaviour of fields, current and charge carriers. For more revision resources, visit the Physics Simulations hub or the A-Level Physics Questions by Topic page.