Answer:
11m
Explanation:
Given:
Resistivity ρ = 5.6e-8 Ωm
Radius r = 0.045 mm [tex]=\frac{0.045}{1000}[/tex] = 4.5 x 10⁻⁵ m
Voltage V = 120V
Current I = 1.24A
From Ohm's law, [tex]R = \frac{V}{I}[/tex]
[tex]R = \frac{120}{1.24}[/tex]
R = 96.77 Ω
Resistivity = (Resistance × Area)/ length
ρ = (RA)/L
Therefore, the length of a wire is given by;
L = (RA)/ρ
Calculating the area A of the wire;
A = πr²
A = π × (4.5 x 10⁻⁵)²
A = 6.36 x 10⁻⁹ m²
Substituting area of the wire A = 6.36 x 10⁻⁹ m² into the equation of the length of wire
L = (96.77 × 6.36×10⁻⁹ ) / 5.6×10⁻⁸
L = 10.9977m
L = 11m (approximately)
