# Shared Flashcard Set

## Details

Magnetic Fields
N/A
17
Physics
Not Applicable
10/20/2012

Term
 WHAT IS A MAGNETIC FIELD?
Definition
 Force field surrounding a magnet or current carrying wire which acts on any other magnet or current carrying wire placed in the field
Term
 WHERE IS THE MAGNETIC FIELD STRONGEST AT?
Definition
 North and south poles
Term
 LINE OF FORCE
Definition
 Path in a magnetic field of which a free north pole would move if acted on by no other force than the force due to the field
Term
 THE EARTH'S MAGNETISM
Definition
 Circulation of currents in molten iron at the core It drifts gradually  currently the north magnetic pole is in northern canada Tectonic plates magnetic field can reverse suddenly
Term
 WHERE IS THE FORCE EXPERIENCED?
Definition
 Current carrying wire placed at an angle to the lines of force experience a force due to field   If it's paralell the force is zero    If it's perpendicular, force is maximum
Term
 MOTOR EFFECT
Definition
 Force perpendicular to wire and line of force   Tested using wire placed between opposite poles of a U shaped magnet so at right angles to line of force and magnetic field
Term
 FLEMING'S LEFT HAND RULE*
Definition
Term
 MAGNETIC FLUX DENSITY
Definition
 Strength of magnetic field Force per unit length per unit current on a current carrying conductor at right angles to the magnetic field lines   F = BiL Gives magnitude (only applies at right angles)    Flemings left hand rule gives direction
Term
 THE COUPLE ON A COIL IN A MAGNETIC FIELD*
Definition
Term
 ELECTRON BEAMS
Definition
 Controlled by magnetic fields Changing current in the coil that controls this will change the strength of the field causing the electrons to change direction
Term
 DEFLECTION
Definition
 Stronger the force, stronger the deflection of the beam of electron. each electron feels a force due to the magnetic field Beam follows circular path because direction of force on each electron is perpendicular to the direction of motion of the electron
Term
 WHY DOES A CURRENT CARRYING WIRE IN A MAGNETIC FIELD EXPERIENCE A FORCE?
Definition
 Because the electrons are pushed to one side by the force in the wire
Term
 HIGH ENERGY COLLISIONS
Definition
 Magnetic fields measure momentum, seperate different charged particles. Positive particles are deflected to opposite sides to the negative ones
Term
 THE ELECTRIC MOTOR
Definition
 Coil of insulated wire that spins between poles of a U magnet Wires at opposite ends of coil are acted on forces in opposite direction Force on each edge makes coil spin around axis WHEN CURRENT PASSES AROUND COIL
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