Physics – 4.5.1 Electromagnetic induction | e-Consult

As the bar magnet approaches the coil, the magnitude of the induced e.m.f. increases. This is because:

• The magnetic flux through the coil increases as the magnet gets closer. The magnetic flux is proportional to the area of the coil and the strength of the magnetic field, both of which increase as the magnet approaches.
• The rate of change of magnetic flux (dΦ/dt) increases as the magnet approaches. The closer the magnet, the faster the magnetic field lines are cutting across the coil's area, leading to a greater rate of change of flux.

According to Faraday's Law of Induction, the induced e.m.f. is proportional to the rate of change of magnetic flux. Therefore, as the rate of change of magnetic flux increases, the magnitude of the induced e.m.f. also increases.