Resistance of a wire

AlR

resistance

resistivity

length

area

Definitions

• Electrical resistance is a measure of the opposition to the flow of electric charge

• Resistivity is a measure of how strong a material resists the flow of electric charge

• Length is the distance between two end of a wire

• Area for a circular wire is

AlR

R

lR AR 1

ρ l A

R R R

Hypothesis

• If I increase the resistivity of the wire, then the resistance will increase

• If I increase the length of a wire, then the resistance will increase

• If I increase the area of a wire, then the resistance will decrease

• (If I increase the reciprocal of the area of a wire, then the resistance of a wire will increase)

Method

• What will I change? This is your independent variable

• What will I measure? This is your dependent variable

• What will you keep the same? This is everything else!