1. Direction of Magnetic Field
Regular Magnet N S

2. Moving Charge induces Magnetic Field
Current thru Coil
Moving Charge induces Magnetic Field

3. Coil Thru Magnetic Field
Moving coil in magnetic field:
Electric current is induced

4. Current thru Coil, w/ Strong Magnet
Moving Magnetic Field induces
Electric Current
Oscillating Magnet induces
Oscillation Current (AC)

5. Magnet & Copper Lenz’s Law: Moving Magnetic Field induces Current
Current induces 2nd Magnetic Field
2 Magnetic Fields Interact

6. Magnetic Induction Moving magnet (field) “causes” current in a wire.
Moving magnet (field) “induces” current in a wire.
Current (moving charge) induces a magnetic field
Current thru a wire can exert a force on a magnet
Magnetic Field can exert a force on a current-carrying wire
Lenz’s Law- moving magnetic field induces a current, which induces a 2nd magnetic field
Moving magnet (field) “causes” current in a wire.

7. Current – interchangeable with velocity
Magnetic Field
Symbol: B
Units: Who cares?
Force
Symbol: F
Units: You’d better know this one!
Velocity
Symbol: v
Current – interchangeable with velocity
Symbol: I
(as in “I don’t know why the symbol for Current is I!”)

8. Up
Down
Left
Right
Out (towards)
In (away)

9. Right Hand Rule #1
How do you tell if the force is up or down on the Positive Charge?
Use the Right Hand Rule #1!
v – thumb
B – index finger
F – middle finger v B F

10. Right Hand Rule #1
A magnetic field (B) will exert a force on a charge only if it is moving perpendicular to the field
As it turns out, the direction of the Force is perpendicular to both B & v F v v F B
Funny- what happens when Force is always perpendicular to v ?

11. Right Hand Rule #1
LEFT
If the charge is negative, then just use your left hand!
Helpful Hint:
Current is considered the flow of POSITIVE charge v B F

12. Right Hand Rule #2 B This is an easy one!
A Magnetic Field wraps around a current-carrying wire I

13. Right Hand Rule #2 What if the wire is not straight, but a loop?
Thumb- B field
Fingers- Current B