Resistance of a wire
Transcript of Resistance of a wire
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!