1. Magnetic Fields Faraday’s Law
Exam 3 Review
Magnetic Fields
Faraday’s Law

2. Magnetic field Field lines come out of the NORTH end of a bar magnet.
Field produced by a wire
Field produced by a loop or a coil
Field produced by a solenoid

3. Magnetic Forces on Moving Charges
Charge q, moving with velocity v in magnetic field B, v makes and angle α wrt B :
Mass spectrometer: v ┴ B, circular path of radius

4. Magnetic Force on Currents
Current carrying wire perpendicular to B
FWIRE = ILB
Force between parallel wires
Currents in same direction attract, opposite repel

5. Magnetic torque on dipole
Θ is the angle between the magnetic field B and the perpendicular to the plane of the loop.
Torque on loop is
Loop lies in a plane
No MRI questions

6. Motional EMF
Straight wire of length L moving perpendicularly to a uniform magnetic field B
EMF = v L B

7. Magnetic Flux
Θ is the angle between perpendicular to loop and the magnetic field

8. Lenz’s Law
Current induced in a loop by a changing magnetic flux creates a magnetic field which opposes the change in flux.

9. Faraday’s Law Changing magnetic flux induces an EMF:
Lenz’s law gives direction
Faraday’s law gives magnitude:

10. Flux changes
Change magnetic field
For a coil:

11. No EM Waves on test