Can Electromagnetic Induction be Reversed?

📌 CONCEPT: Electromagnetic induction refers to the process by which a changing magnetic field induces an electromotive force (EMF) in a conductor, such as a coil of wire. This phenomenon is the basis for many electrical devices, including transformers.

📐 RULE / FORMULA: The key principle governing electromagnetic induction is Faraday's law of electromagnetic induction, which states that the induced EMF in a conductor is proportional to the rate of change of the magnetic flux through the conductor. The formula is EMF = -N(dΦ/dt), where N is the number of turns of the coil and Φ is the magnetic flux.

💡 WORKED EXAMPLE: Consider a transformer with 100 turns of coil connected to a power source. If a magnet is placed near the coil, inducing a magnetic flux of 10 Wb, and the power source is removed, the magnetic flux will decrease rapidly. Using Faraday's law, we can calculate the induced EMF: EMF = -100(10 Wb/1 s) = -1000 V. As the magnet is removed, the induced voltage in the coil will increase to a maximum value and then decrease to zero.

⚠️ COMMON MISTAKE: Students often incorrectly assume that the induced voltage in the coil will remain the same when the magnet is removed, as they neglect the rapid change in magnetic flux.