Question

What is the resistance of a 3.1 m length of copper wire 1.7 mm in diameter?

Answer 1

R = ?
L = 3.1 m;
r = 1.7 mm/ 2 = 0.85 mm = 0.85 * 10^(-3) m
Resistivity of copper ( rho ) = 1.68 * 10 ^(-8) [Ohm m ]
A = 3.15 * ( 0.85 * 10^(-3))^2 = 2.26865 * 10 ^(-6)
R = ( Rho ) * L / A = 1.68 * 10^(-8) * 3.1 m / 2.26865 * 10^(-6) =
= (1.7 * 3 .1 / 2.26865 )* 10^(-2) = 0.02323 Ohms ( the resistance )