Presentation on theme: "Magnetic Fields Faraday’s Law"— Presentation transcript:

Exam 3 Review Magnetic Fields Faraday’s Law

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

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

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

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

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

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

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

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

Flux changes Change magnetic field For a coil:

No EM Waves on test