G) Generator Principle - Electromagnetic Induction
1831 - Michael Faraday discovered that current and voltage can be induced when a conductor (closed loop) moves within a magnetic field.
© Copyright 1997, Sergey Kiselev and Tanya Yanovsky-Kiselev
http://www.walter-fendt.de/ph11e/generator_e.htm © Walter Fendt, May 8, 1998
(Note: 3 dimensional view)
Wire is perpendicular to page
If this wire is moved up or down (perpendicular to the field), maximum current will be generated.
If it's moved left or right (parallel to the field), no current will be generated
How to find the direction of current - Third Left Hand Rule
Step 1: flux lines - Out of N into S
Step 2: 4 fingers follow flux lines
Step 3: Thumb follows movement of wire (Given)
Step 4: Palm shows Push on electrons - The current direction
Ex) If the wire in the picture above is moved upward, which way will the electrons flow?
Into the page OR Out of the page?
Out of Page
Direction of induced current?
Down
(V) Induced voltage - also called EMF - Electromotive Force
V = Blv
On Reference Table
B - Magnetic Field Strength
l - length of conductor (in meters)
v - velocity of conductor moving through the field
Lenz’s Law - The magnetic field around induced current opposes the wire motion that produced it.
All the left hand rules only work when the moving charges are negative.
What do you do when the moving charge is positive?
Right Hand Rule!
Video
Levitation - HyperPhysics