Respuesta :
Given Information:
Radius of copper wire = r = 0.11 mm = 0.11×10⁻³ m
Length of copper wire = L = 20 m
Required Information:
Resistance of the copper wire = R = ?
Answer:
Resistance of the copper wire = R = 18.1 Ω
Explanation:
The resistance of the copper wire is given by
[tex]R = \rho \frac{L}{A}[/tex]
Where ρ is the resistivity of the copper wire and is equal to 1.72×10⁻⁸ Ω/m at 20 ˚C, L is the length of the wire and A is the area of the wire and is given by
[tex]A = \pi r^{2}[/tex]
Since the wire is used to connect speaker to the amplifier, two wires would be needed and the length of the wire becomes
[tex]L = 2\times 20 = 40\: m[/tex]
Finally, the resistance of the wire is
[tex]R = \rho \frac{L}{\pi r^{2}}\\\\R = 1.72\times10^{-8}\cdot \frac{40}{\pi (0.11\times10^{-3})^{2}}\\\\R = 1.72\times10^{-8}\cdot 1.052\times10^{9}\\\\R = 18.1 \: \Omega[/tex]
Therefore, the minimum resistance of the connecting wires is 18.1 Ω
Answer:
Resistance = 181.8 ohms
Explanation:
R = L/r
R = 20/0.11
R = 181.8 ohms
