phys_MAGNETISM

Dipolar

magnets are _____; two poles, usu. referred to as N and S

monopole

magnets cannot be _______.
only one pole

Hard metals

difficult to magnetize, but retain magnetism for a long time

Soft metals

easy to magnetize, but lose magnetism quickly

Ferromagnetic

(fer = IRON)
*only iron and a few other materials show strong, easily measureable magnetic effects

Magnetic Field

Direction of the force on the north pole of a magnet

(moves from north pole to south pole)

*produced by current

magnetic declination

b/c magnetic poles don't match evenly with opposite geographic poles; always an angle of error

*the angular difference btwn magnetic north and true north

How much work does a magnetic force do?

ALWAYS zero work! because magnetic force is always perpendicular to the path of motion

Induced current

current produced because of changing current in nearby wire

Electromagnetic induction

process of creating current from magnetic field

Magnetic flux

dot product of the magnetic field and the area of the loop;

measure of how much magnetic field passes through a specific area of space

*WEBER

Faraday's law of induction

emf = number of loops times rate of change of magnetic flux

Lenz's Law

induced emf will always create a current whose magnetic field opposes the original change in flux

Ways of increasing magnetic flux?

1) increase area of loop
2) increase strength of magnetic field
3) rotate the loop