Objects can be charged
positively or negatively
by transforming
electrons.
Like charges repel
and unlike
charges attract.
An electric field is a
region where there is a
force on charged
particles or materials.
Electric current is the
amount of charge
flowing per second. You
measure current in amps
(A) using an ammeter.
The potential difference of
a cell tells you the size of
the push on the charges
and how much energy can
be transferred by them.
You measure potential
difference in volts (V) using a
voltmeter. The rating of a
cell or battery tells you the
potential difference at
which it operates.
Series circuits contain
only one loop, and the
current is the same
everywhere. Parallel
circuits have branches
and the currents in all
the branches add up to
the total current.
A component with a high resistance
has a small current through it.
Resistance is measured in ohms(__)
You calculate the resistance using
potential difference across a
component and the current through
it. Insulators have a very high
resistance and conductors have a
very low resistance.
Magnets have a north
pole and a south
pole. Like poles repel
and unlike poles
attract.
Magnetic materials feel a
force in the region
around a magnet called a
magnetic field.
A current flowing in a coil
of wire wrapped around
a magnetic material is an
electromagnet. It
behaves like a bar
magnet, but you can turn
it on and off.
Electromagnets
are used in
maglev trains,
hospitals and
cars.