Ohm's Law Study Guide

Science

Ohm’s law

Current: amount of electrical charges(electrons) flowing around the circuit

Voltage: size of the force pushing the electrons around the circuit

Resistance: measure of how difficult it is for electrons to flow around the circuit

Ohm’s law is when electric current in the metallic conductors were proportional to the voltage drop across the conductor.

If the voltage was doubled the current was doubled.

In ohmic resistors, light gloves are non-ohmic because as they get hotter their resistance changes.

ex) the fine filament in a light globe, because as it heats up the resistance changes.

[metals and carbon are ohmic materials as long as the temperature remains fairly constant]

To work out if a material is ohmic:

Draw a graph of voltage drop versus electric current. If the material is ohmic, a graph of V versus I yields a straight line because resistance is constant.

Circuit

Ammeter: measures electrical current [measuring device]

-connected in series in a circuit

Voltmeter: measures electrical potential difference [measuring device]

-connected in parole in a circuit

Battery/powerpack: produces electrical energy [energy suppliers]

Globe: changes electrical energy into light and heat [energy users]

Switch: gate in a circuit to turn off the current [circuit