Summary OCR A level Physics A 6.3 Electromagnetism

6.3 Electromagnetism

, Magnetic fields

Magnetic field lines map magnetic field patterns around magnets and
current conductors
carrying
-
.




•
Arrow / direction of magnetic field is the direction in which a free north
pole would move ( north to south
Equally spaced parallel magnetic field lines represent a uniform magnetic
•




field magnetic flux density is the same throughout the field
-




•
The magnetic field strength is stronger when the magnetic field lines are
closer
together .




Like
poles repel and
opposite poles attract
• .




Current carrying -
conductors


for a current -




carrying wire .
the magnetic field lines are circular centred
,
on the
wire and perpendicular to it .




Direction of magnetic field determined the hand NK where
can be
using right grip
-




the thumb conventional current and the
points in the direction of fingers curve in the

direction of the magnetic field


✓ ✓ ✓ ^ ✓ ✓ ~
• n r n ^
n
og




out of paper into paper




the strength of a
magnetic field is known as
magnetic flux density and
is measured in tesla ( ) t .




When current conductor is placed perpendicular to external
a
carrying an
-




magnetic field ,
the direction of the force can be found using Flemming 's
left -


hand rule .