Ohm's+Law

=Ohm's Law=

Ohm's Law describes the relationship between voltage, resistance, and current in a circuit.




 * When voltage increases, the current goes up. When the resistance increases (another light bulb is added), the current goes down.
 * Ohm's Law describes how much current flows for different amounts of voltage.
 * If an electrical device has the same resistance under different conditions, it is said to obey Ohm's Law. However, if the resistance changes, the electrical device doesn't obey Ohm's Law.
 * A current vs. voltage graph can be used to determine if an electrical device obeys Ohm's Law. If the current vs. voltage graph is a straight line, then the electrical device obeys Ohm's Law. Simple resistors obey Ohm's Law, but diodes do not.
 * Resistance is caused because the charges collide with atoms as they travel through the material. Even if a material obeys Ohm's Law, its resistance will increase when temperature increases. This is because the atoms of the material move around more at higher temperatures and collide more often with the moving charges.

I = V/R
V = voltage (V, volts) I = current (A, amps) R = resistance (ohms)

1) A lightbulb with a resistance of 2 ohms is connected to a 1.5 volt battery. Calculate the current that will flow.

Answer

2) A lightbulb requires 3 amps to produce light. The resistance of the bulb is 1.5 ohms. How many batteries do you need if each battery is 1.5 volts?

Answer

(The above problems are from the CPO Integrated Physics and Chemistry textbook).