With no magnetic field, the sodium
flame aborbs
light from the sodium lamp and the image on the screen is of a dark
flame
in the yellow background from the lamp. As the field strength is
increased to
several kilogauss, absorption lines shift and shadow brightens,
disappearing
into the background.
NOTES
Sodium flame is produced by salt on
rim of
propane torch, or salt chunks inside rim.
Propane torch must be securely clamped
so
it does not move in the magnetic field.
Place polaroid with its axis vertical
in front
of sodium lamp.
Set variac to minimum voltage
necessary for
sodium lamp (~ 50 V) to reduce line-broadening.
Turn on cooling water before turning
on power
supply for electromagnet. Turn power supply up to 50 A for
sufficient
shift in absorption spectrum of flame.
