Physics ohm’s law
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Transcript of Physics ohm’s law
It is the rate of flow of electric
charge through a medium.
This charge is typically carried by
moving electrons in a conductor
such as wire.
Current flows from negative to
positive on the surface of a conductor. It is measured in
amperes or amps.
A circuit needs three
things to work:
1. Power source
2. A closed conductive
path
3. Resistor/Load
Also called as:
Electric Potential difference
Potential drop
Electrical potential
difference and;
Electrical potential
Voltage is the difference
in electrical potential
between two points, or
the difference in
electrical potential
energy unit charge
between two points.
Resistance is how much an
object resists the flow of
electrons.
It is the inverse of conductance.
It measures how difficult it is for
electrons to flow through a
material. It is measured in
ohms.
Conductor – a material which
contains movable electrical
charges. In metallic
conductors such as copper
and aluminum, the movable
charged particles are
electrons
Insulator – a material that is
a poor conductor of
electricity.
›An insulator, such as
ceramic or rubber, has high
resistance and poor
conductance. A metal has
low resistance and high
conductance
Resistors – objects that
are designed to have
a specific resistance
so that they can
dissipate electrical
energy or modify how
a circuit behaves
The nature of the material = Some
materials are better conductors than
others, causing less resistance
The thickness of the conductor/wire =
The larger the wire, the less resistance;
the bigger the cross-sectional area of
the wire the greater the number of
electrons that experience the ‘electric
slope’ from the potential difference.
The length of the
conductor/wire
= The longer the
wire, the more
resistance. The
longer the wire,
the less the volts
each
centimeter of it
will get.
The temperature =
Heat affects resistance; the
higher the
temperature, the higher the
resistance
Ohm’s Law describes
mathematically the
relationship between
current and voltage
(potential difference).
I is the current through the
conductor in units of
amperes;
V is the potential difference
measured across the
conductor in units of volts;
and
R is the resistance of the
conductor in units of ohms.
The potential difference
(voltage) is
proportional to the
current through it. The
current is indirectly
proportional to
resistance.