1. Unit 5 Day 2: Induced EMF in a Moving Conductor Induced EMF in a Moving Conductor in a Magnetic Field Force Required to Move a Moving Conductor in a Uniform Magnetic Field Electric Generators (AC)

2. Induced EMF in a Moving Conductor in a Magnetic Field The B-Field is out of the paper and perpendicular to a U- shaped conductor with a movable rod, moving at velocity v. The area of the loop increases as it travels to the right This equation is valid if B, l, v are mutually perpendicular. This EMF is called motional EMF

3. Induced EMF in a Moving Conductor in a Magnetic Field The magnetic force on the electrons on the rod is given by: where q is the charge on the rod When the rod moves to the right with velocity v, electrons in the rod also move with this speed & feel the force Another approach to calculating the EMF, is to determine the work done to move a charge q, from one end of the rod to the other:

4. The Force Required to Move a Conducting Rod in a Uniform Magnetic Field To make the rod move to the right an external force must be applied in the direction of motion The power delivered to move the rod equal the power dissipated in the resistance of the rod.

5. Electric Generators (AC) A mechanically turned armature, consisting of N-loops of a coil wound on the armature As the armature is rotated, an EMF is induced in the rotating coil, which alternates as the magnetic flux through the loop reverses. The induced EMF is:

6. Electric Generators (AC) The induced EMF is a sinusoidal voltage A typical AC Generator (Alternator):