What is Faradayâ€™s Law of Electromagnetic Induction?

Faraday’s law explains how a magnetic field interacts with an electric circuit to create an electromotive force (EMF). This process is called electromagnetic induction. Michael Faraday introduced these laws in 1831 through experiments that showed how changing magnetic fields generate electric currents.

Faradayâ€™s Laws of Electromagnetic Induction

Faraday’s laws include two main principles:

First Law:

Whenever a conductor is placed in a changing magnetic field, an EMF is induced. If the conductor circuit is closed, it will cause an induced current.

Second Law:

The induced EMF in a coil is equal to the rate of change of magnetic flux linkage.

The formula for Faradayâ€™s second law is:

WhereÂ

is the EMF,Â

is the magnetic flux, andÂ

is the number of turns in the coil.

Lenzâ€™s Law

Heinrich Lenz formulated Lenzâ€™s law to describe the direction of the induced EMF. It states that the direction of the induced EMF will always oppose the change in magnetic flux that caused it. This is represented by the negative sign in Faraday’s second law.

Derivation of Faradayâ€™s Law

If a magnet approaches a coil:

At time T1, the flux linkage is

At time T2, the flux linkage is

The change in flux linkage is

The rate of change of flux linkage is

Taking the derivative, we get:

Key Points:

• More turns in the coil increase the induced EMF.
• Stronger magnetic fields increase the induced EMF.
• Faster relative motion between the coil and the magnet increases the induced EMF.

1. Magnetic Field Strength Change: Moving a magnet towards a wire loop induces current, shown by a deflecting ammeter.
2. Electromagnetism: Passing current through an iron rod creates an electromagnet. Rotating a magnet induces EMF; a stationary magnet does not.
3. Relative Motion: The ammeter deflects when the magnet moves away from the loop, indicating induced EMF.

Applications of Faradayâ€™s Law

1. Transformers: Electrical equipment that changes voltage levels.
2. Induction Cookers: Heat food using electromagnetic induction.
3. Electromagnetic Flowmeters: Measure the flow rate of fluids.
4. Musical Instruments: Electric guitars and violins use Faraday’s principle.
5. Maxwellâ€™s Equation: Shows that changing magnetic fields produce electric fields.

FAQs

What was the outcome of Faradayâ€™s experiments?2024-08-05T11:50:10+05:30

What was the outcome of Faradayâ€™s experiments?

Faraday concluded that a relative motion between a conductor and a magnetic field changes the flux linkage, producing a voltage across the coil.

What are some applications of Faradayâ€™s law?2024-08-05T11:49:39+05:30

What are some applications of Faradayâ€™s law?

Faradayâ€™s law is applied in transformers, induction cookers, electromagnetic flowmeters, electric guitars, and Maxwellâ€™s equations.

How does the number of turns in a coil affect the induced EMF?2024-08-05T11:49:09+05:30

How does the number of turns in a coil affect the induced EMF?

Increasing the number of turns in the coil increases the induced EMF.

What does Lenzâ€™s law state?2024-08-05T11:48:45+05:30

What does Lenzâ€™s law state?

Lenz’s law states that the induced EMF will always oppose the change in magnetic flux that caused it.

What are the main principles of Faradayâ€™s laws?2024-08-05T11:48:21+05:30

What are the main principles of Faradayâ€™s laws?

The first law states that an EMF is induced when a conductor is placed in a changing magnetic field. The second law quantifies the EMF as the rate of change of magnetic flux linkage.

What is Faradayâ€™s law of electromagnetic induction?2024-08-05T11:46:36+05:30

What is Faradayâ€™s law of electromagnetic induction?

Faraday’s law states that a changing magnetic field creates an electromotive force (EMF) in a conductor.