Resistance

Resistance

Open Ended

Calculate the potential difference between two points when 480 J of energy are required to move a 12 C charge.

Open Ended

Calculate the charge that moves through a certain point in 3 seconds when a current of 2 A is produced.

Main Components of an electric circuit.

• Potential Difference

• Current

• Resistance

Resistance

• Resistance: the measure of the difficulty of current to flow

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Open Ended

When thinking about a good and effective wire, based on the definition, should wires have low resistance or high resistance? Why?

Resistivity

Wires are made of metals, and metals are composed of atoms with mobile electrons.  Those electrons moving around the wire can cause “traffic.”  Resistivity is the measure of how much the material slows down the current.

Open Ended

When thinking about a good and effective wire, should the material have a low or a high resistivity? Why?

Area

The area of the wire (thickness) is also important when determining the resistance of a wire.  Once again, we will look at the “traffic” example.  For example, an ambulance needs to get through.  Where is it easier for the ambulance to travel?

Open Ended

If the cars are analogous to electric current, would good and effective wires ideally thicker or thinner? Why?

Length

The length of the wire is the third important factor in determining the resistance of a wire.  If we once again use the “traffic” example, do longer roads make it easier for an ambulance to get to its destination?

Open Ended

If the length of the road is analogous to the distance that must be travelled by an electric current, are good and effective wires longer or shorter? Why?