What is the resistance of a copper wire, diameter of 1.50mm and length of 25.0 m?
i got R=pl/A R=p(25m)/(3.14*(.00075^2)) how ever i found the answers online and they give me this
(1.68*10^-8)(25.0)/(3.14*(.00075^2))
and what is your question?
ah never mind i mixed up p wiht power instead of resistivity.
To calculate the resistance of a copper wire, you can use the formula: R = (ρ * L) / A, where R is the resistance, ρ is the resistivity of copper, L is the length of the wire, and A is the cross-sectional area of the wire.
In this case, you have the diameter of the wire (1.50 mm) and the length of the wire (25.0 m). To find the resistance, you need to convert the diameter into the radius and then calculate the cross-sectional area.
First, convert the diameter (1.50 mm) into meters by dividing it by 1000:
diameter = 1.50 mm / 1000 = 0.00150 m
Next, calculate the radius by dividing the diameter by 2:
radius = 0.00150 m / 2 = 0.00075 m
To find the area, use the formula for the area of a circle: A = π * r^2
area = π * (0.00075 m)^2 = 3.14 * (0.00075^2) m^2
Now you can substitute the given values into the resistance formula:
R = (ρ * L) / A
The resistivity of copper, ρ, is approximately 1.68 * 10^-8 Ω∙m.
Substituting the values:
R = (1.68 * 10^-8 Ω∙m) * (25.0 m) / (3.14 * (0.00075^2) m^2)
Now you can simplify and calculate the resistance.
If you found different answers online, it could be due to rounding errors or different values used for the constants. Make sure you are using the correct values for the resistivity of copper and the mathematical constants.