CH 5 – Electricity and Magnetism Electrical Circuits CH 5 – Electricity and Magnetism

Ohm’s Law V = IR V: I: R:

Resistors in Circuits Series Parallel

Resistance and Conductance A resistor resists (slows down or stops) the flow of electrons. Insulators are resistors. Ex: Plastic, glass, ceramic, tungsten, wood, distilled water (water with no electrolytes) Conductors conduct (allow for) the flow of electrons. Ex: Metals (copper, gold, etc.), acidic and basic solutions, salt water, (water with electrolytes) A good conductor is a poor resistor and a good resistor is a poor conductor

Factors that affect resistance and conductance Type of wire: different types of material conduct electrons better Metal wire (gold is best, copper is cheap and good) Non-metal material (wouldn’t conduct)

Factors that affect resistance and conductance Length of wire: longer wire = more distance resisting electron flow Short wire Long material

Factors that affect resistance and conductance Diameter of wire: wider and larger wires conduct better Thick wire Thin wire

Factors that affect resistance and conductance Temperature of wire: the hotter the wire, the more resistance there is Cold wire Hot wire

So the best wire would be… Metal (gold), short, thick, cold

Finding the resistance when resistance graph is given.

Finding resistance when conductance graph is given.

Finding resistance when a table is given.