Electromagnetic Induction For Jamb Physics

In this episode of my Jamb series, I will be introducing you to Electromagnetic induction as one of the topics Jamb sets in her CBT examination.

1. Faraday’s Law: One of the foundational principles of electromagnetic induction is Faraday’s law. Proposed by the English scientist Michael Faraday, this law states that a change in the magnetic field within a conductor induces an electromotive force (EMF) or voltage in the conductor. This EMF creates an electric current if the conductor forms a closed loop.

2. Magnetic Field and Flux: A magnetic field is a region surrounding a magnet or a current-carrying conductor where the influence of magnetism can be detected. When a magnetic field changes in strength or direction, it creates a change in magnetic flux, which is the measure of the magnetic field passing through a given area. It is this change in magnetic flux that induces an EMF in a nearby conductor.

3. Induced Voltage and Current: As the magnetic flux through a conductor changes, an induced voltage is created across the ends of the conductor. This induced voltage, in turn, drives an electric current to flow through the conductor. The magnitude of the induced voltage and current depends on factors such as the rate of change of magnetic flux and the characteristics of the conductor.

STUDY SMARTER

Now, let’s delve into a practice question to solidify our understanding:

Practice Question: Consider a stationary coil of wire placed near a magnet. What happens when the magnet is moved closer to the coil?

Explanation: When the magnet is moved closer to the stationary coil of wire, the magnetic field passing through the coil increases. According to Faraday’s law of electromagnetic induction, this change in magnetic field induces an electromotive force (EMF) in the coil. As a result, an electric current is generated in the coil, flowing in a direction that opposes the change in the magnetic field. This phenomenon is known as electromagnetic induction.

By understanding the basic definitions and concepts of electromagnetic induction, as well as applying them to practice questions, you can develop a solid foundation in this topic. Electromagnetic induction plays a crucial role in various applications, including generators, transformers, and electric motors, and further exploration of this subject will reveal its significance in the field of electromagnetism.

In electromagnetic induction, current is produced without battery. There is one important fact you should note.. Electromagnetic Induction is the reverse effect of magnetic effect of current.

In addition, Electromagnetic induction is the process whereby current is produced in a conductor due to relative motion with a magnet. Hence, no current is induced when the magnet and the conductor are both stationary or both moving with same speed in the same direction.

Like you already know, conductors are materials that allow the passage of current through them easily. Insulators, on the other hand, has a strong resistance to the flow of electrons or current due to large forbidden band/gap.

Question for You: What gives rise to induced current in a complete circuit?