4. THE MAGNETIC FIELD 𝑩
A magnetic field is said to exist at a point if a compass needle
placed there experiences a force. It is measured in Tesla (T)
We call the lines along which the magnets align themselves
the magnetic field lines.
5. MAGNETIC FIELD
Magnetism is the force that moving charges exert on one
another.
Recall that electricity is (in essence) the force that charges
exert on one another. Since this force exists whether or not
the charges are moving, it is sometimes called the
electrostatic force. Magnetism could be said to be an
electrodynamic force
6. MAGNETIC FIELD
Electric charges are the source of electric fields and that
other charges experience an electric force in those fields.
The charges generating the field were assumed to be at
rest.
Electric charges that move are the source of magnetic
fields, and other charges that move can experience a
magnetic force in these fields
9. UNITS
The SI unit for the magnetic field is
the tesla (abbreviated T), which is one newton per
ampere-meter. Another common unit for magnetic field
strength is the gauss (abbreviated G); 1 G = 10–4 T.
1 T = 1 N·s/(C·m)
m
C
s
N
s
m
C
N
