# If I had current and voltage how would I find the resistance?

Jul 11, 2017

Use Ohm's Law: $V = I R$. Resistance R is the load or that section of the circuit which opposes the flow of current I resulting when a voltage V is applied.

#### Explanation:

To build a simple electric circuit you would need a battery to supply the voltage or electromotive force. When connected to a couple of wires at the battery terminals the battery would try to push electrons down one wire and collect them at the other wire.

But do not connect the two wires yet! To complete this circuit you would need a load across the two wires, such as a light bulb. This would be the resistance in the circuit. Without the resistance, you would have a short circuit which could burn out the battery or blow a fuse.

As the voltage pushes the electrons, they flow in a current through the resistor (light bulb) and cause it to glow. The bulb glows because the resistance of the bulb filament is very low, so the wire heats up enough in a protective gas to produce light.

If: I = current, R = resistance, V = Voltage; then: $V = I R$.

You have I and V, and you need R, so divide both sides by I:

Then: $V = I R \to$ $\frac{V}{I} = \frac{\cancel{I} R}{\cancel{I}} \to$ and now $R = \frac{V}{I}$