Earth’s Magnetic Field
The Earth’s geographic north pole corresponds
to a magnetic south pole
The Earth’s geographic south pole corresponds
to a magnetic north pole
Strictly speaking, a north pole should be a
“north-seeking” pole and a south pole a
“south-seeking” pole
Quick Quiz
The red end of a compass needle which points
“North” is which end of a dipole magnet?
A. North pole
B. South pole
Electric Charges in Magnetic Fields
Moving charges feel magnetic force
perpendicular to path of
This force has a maximum value when
the charge moves perpendicularly to the
magnetic field lines
This force is zero when the charge moves
along the field lines
This force is zero if the charge is stationary
F = Bqv sin θ
Superconducting magnets
300000 Gauss or 30 Tesla
Earth’s magnetic field
-5 T
0.5 G or 5 x 10
Quick Quiz
How many G in a T?
D. 105
A.10-5
E. 0.5 x 10-5
B.10-4
4
C.10