ELECTRIC
POTENTIAL
Electric force

Electric force is the force that pushes apart two like
charges, or that pulls together two unlike charges.

The size of this attraction decreases as the distance
between them increases.
Electric field

The electric field is a “force field” around a charged
object that illustrates the direction the electric force.
Electric potential energy

Electric potential energy is the energy that is
needed to move a charge against an electric field.

Electric potential energy results from the interaction
of two objects’ charges.

You need more energy to move a charge further in
the electric field, but also more energy to move it
through a stronger electric field.
What is electric potential?





The electric potential, or voltage, is the difference in
potential energy per unit charge between two
locations in an electric field.
SI unit is volts (V)
Voltage describes the “pressure” that pushes
electricity.
The amount of voltage is indicated by a unit known
as the volt (V), and higher voltages cause more
electricity to flow to an electronic device.
Voltage is the pressure from an electrical power
source that pushes charged electrons (current)
through a conducting loop.
Current

A continuous flow of free electrons, through the
conductors of a circuit.

Current is a general characteristic of electricity.

To define current more precisely, suppose electrons
are moving through a wire.

SI unit of current is amperes (A)
Current

CHARGE IN MOTION IS CURRENT

Potential difference across two ends of wire
conductor causes drift of free electrons
throughout the wire to produce electric current.

Electric current is the rate at which electric
charges pass through a given area.
Note: the flow of
current is always
opposite the
movement of
negative charge.
Resistance

RESISTANCE TO CURRENT

RESISTANCE is the opposition presented to electric
current by a material or device, or the ability of a
material to oppose charge flow

The SI units for resistance is the ohms (Ω) (omega
symbol)

Resistors can be used to control the amount of
current in a conductor.

Resistance depends on length, area, material, and
temperature.
Ohm’s Law

The mathematical relationship between electric
current (I), resistance (R), and voltage (V).

Ohm’s law states that the current through a
conductor, between two points is directly
proportional to the voltage across the two
points.

It is named after the German scientist Georg
Simon Ohm.
Ohm’s law formula

V=IxR

V is voltage

I is current

R is resistance
Which Way Does Electricity Flow?

A continuous flow of free electrons, through the
conductors of a circuit is called a current. An
electric circuit is formed when a conductive
path is created to allow the free electrons to
continuously move.

The force that is motivating the flow of electrons
is called voltage, or electric potential.

Free electrons tend to move through
conductors with some degree of friction, or
opposition to the motion. This opposition to
movements of free electrons is called
resistance.
Solve for the resistance in this circuit.
Given:
Work:
Formula:
Answer:
Example 2

Calculate the voltage if the current is 0.5 A and the resistance is 2 Ω.

Given:
Work:

Formula:
Answer: