ELECTRIC CURRENT - Mr. Shanks' Class



ELECTRIC POTENTIAL DIFFERENCE (VOLTAGE)

Why can you touch the ends of a battery and not get an electric shock, but if you touch a wall outlet you would get a major shock?

THE WATER WHEEL MODEL

WATER WHEEL vs ELECTRIC MOTOR

- the water gains gravitational - the electrons gain electric potential

potential energy while going energy while going through the dry

through the pump cell (battery)

- the energy transferred to the - the energy the electrons gain

water by the pump is used from the dry cell is used to turn

to turn the water wheel the electric motor

HOW IS ENERGY MEASURED?

All forms of energy are measured in JOULES (J).

Recall that electrons are bundled in to groups called COULOMBS (C).

The amount of energy that each coulomb has is called the electric potential energy. The symbol for this is V.

Example: Let’s say that 1 coulomb passed through a battery and gained 9 joules

of energy. What would be the electric potential energy as it exited

the negative terminal of the battery?

Electric Potential Energy (V) = 9 Joules = 9 J = 9 J/C = 9 Volts

1 Coulomb 1 C

Electric potential energy is measured in Volts, which also has the symbol V.

(1 V = 1 J/C)

ELECTRIC POTENTIAL DIFFERENCE

This is the difference in electric potential energy between any two points in a circuit. This is also referred to as the voltage.

Example: A 1.5 Volt battery

Each coulomb entering the Each coulomb leaving the

positive terminal has 0 joules the negative terminal has

of energy 1.5 joules of energy

A B

We call it a 1.5 Volt battery because the electric potential difference (voltage) between the negative (point B) and positive

terminal (point A) is 1.5 volts.

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