Faraday’s Law of Induction

A changing magnetic field induces an electric field. The induced electric field causes a current to flow in a conductor.

Lenz’s Law

A changing magnetic field induces a current, which in turn produces

a second magnetic field which opposes any further change in the

first.

Application of Lenz’s Law

A magnet is pushed into a coil as shown below. What is the direction of the induced magnetic fieldmagnetic field in the coil?

Application of Lenz’s Law

A magnet is pushed into a coil as shown below. What is the direction of the current inducedcurrent induced in the coil?

Application of Lenz’s Law

A magnet is pushed into a coil as shown below. What is the direction of the current induced in the coil?

Application of Lenz’s Law

A magnet is pushed away from a coil as shown below. What is the direction of the induced magnetic fieldmagnetic field in the coil?

Application of Lenz’s Law

A magnet is pushed into a coil as shown below. What is the direction of the current inducedcurrent induced in the coil?

Application of Lenz’s Law

A magnet is pushed into a coil as shown below. What is the direction of the current induced in the coil?

TransformersGiven the current as shown in the primary coilprimary coil, determine the

direction of the magnetic field induced in the iron coreiron core .

TransformersGiven the current as shown in the primary coil, determine the

direction of the magnetic field induced in the iron core .

TransformersGiven the induced magnetic fieldinduced magnetic field as shown, determine the direction

of the current induced in the secondary coilsecondary coil .

TransformersGiven the induced magnetic field as shown, determine the direction

of the current induced in the secondary coil .

For a transformer,PP = PS

IP VP = IS VS

IP / IS = VS / VP = NS / NP