# ohms law

## using ohms law to calculate current

You can use the equation for current (above) to calculate the amount of current flowing through a circuit when the voltage and resistance are known. Consider an electric wire that is connected to a 12-volt battery. If the wire has a resistance of 2 ohms, how much current is flowing through the wire? Current = 12 volts 2 ohms = 6 amps Q: If a 120-volt voltage source is connected to a wire with 10 ohms of resistance, how much current is flowing through the wire? A: Substitute these values into the equation for current: Current = 120 volts 10 ohms = 12 amps

## understanding ohms law

Ohms law may be easier to understand with an analogy. Current flowing through a wire is like water flowing through a hose. Increasing voltage with a higher-volt battery increases the current. This is like opening the tap wider so more water flows through the hose. Increasing resistance reduces the current. This is like stepping on the hose so less water can flow through it.

## introducing ohms law

For electric current to flow through a wire, there must be a source of voltage. Voltage is a difference in electric potential energy. As you might have guessed, greater voltage results in more current. As electric current flows through matter, particles of matter resist the moving charges. This is called resistance, and greater resistance results in less current. These relationships between electric current, voltage, and resistance were first demonstrated in the early 1800s by a German scientist named Georg Ohm, so they are referred to as Ohms law. Ohms law can be represented by the following equation. Current(amps) = Voltage(volts) Resistance(ohms)

## instructional diagrams

No diagram descriptions associated with this lesson

## questions

a source of voltage is required for an electric current to flow.

-->  a. true

b. false

the amount of current flowing through a wire will be less when there is greater

a) voltage.

-->  b) resistance.

c) electric potential energy.

d) two of the above

which equation represents ohms law?

a) current = voltage x resistance

-->  b) current = voltage/resistance

c) current = resistance/voltage

d) none of the above

ohms law can be used to calculate current when voltage and resistance are known.

-->  a. true

b. false

assume that an electric wire is connected to a 9-volt battery and the wire has a resistance of 3 ohms. how much current is flowing through the wire?

a) 27 amps

b) 12 amps

c) 9 amps

-->  d) 3 amps

## diagram questions

No diagram questions associated with this lesson