Answer:
[tex]L=4.8*10^{17}m[/tex]
Explanation:
Given data
Power P=4.00×10²W
Radius r=6.5×10⁴m
Voltage V=120V
To find
Length of wire L
Solution
We know that resistance of wire can be obtained from
[tex]P=\frac{V_{2}}{R}\\ R=\frac{V_{2}}{P}[/tex]
We also know that R=pL/A solving the length noting that A=πr²
and using p=100×10⁻⁸Ω.m we find that
So
[tex]L=\frac{RA}{p}\\ L=\frac{\frac{(V^{2})}{P}(\pi r^{2}) }{p} \\L=\frac{V^{2}(\pi r^{2})}{pP}\\ L=\frac{(120V)^{2}\pi (6.5*10^{4} m)^{2} }{100*10^{-8}(4.00*10^{2} W) }\\ L=4.8*10^{17}m[/tex]
