Electromagnetic Induction

What defines Magnetic Flux (Φ)?

Magnetic Flux (Φ) is the total number of magnetic field lines passing through a given area, defined as Φ = ABcos Θ.

What is the formula for Flux Linkage (NΦ)?

Flux Linkage (NΦ) is defined as NΦ = NABcos Θ, where N is the number of turns.

What does Faraday’s Law state about induced electromotive force (emf)?

Faraday’s Law states that the induced emf in a circuit is proportional to the rate of change of magnetic flux linkage.

How is emf calculated according to Faraday’s Law?

emf is calculated as emf = − (NΦ) / t.

What does Lenz’s Law indicate about the direction of induced emf?

Lenz’s Law indicates that the induced emf acts in a direction to oppose the change in flux that caused it.

What is the expression for induced emf when magnetic flux linkage changes over time?

The expression is emf = − d(NΦ) / dt.

What are some applications of Faraday’s and Lenz’s Laws?

Applications include transformers, electric generators, and induction heating.

What occurs when a conductor moves perpendicularly to a magnetic field?

An emf is induced in the conductor when it moves at right angles to a uniform magnetic field.

What is the formula for induced emf in a moving linear conductor?

emf = Blv, where B is the magnetic flux density, l is the length of the conductor, and v is the velocity.

How does rotation of a coil in a magnetic field affect flux linkage?

Rotation changes the flux linkage sinusoidally.

What is the formula for instantaneous emf in a rotating coil?

emf = NAB ω sin(ωt), where N is the number of turns, B is flux density, A is coil area, ω is angular velocity, and t is time.

When does maximum emf occur in a rotating coil?

Maximum emf occurs when the coil is parallel to the field lines.

When is the emf zero in a rotating coil?

The emf is zero when the coil is perpendicular to the field, resulting in no flux change.