How much current will flow through a 40.0-m length of metal wire with a radius of $0.0 \mathrm {~mm}$ if it is connected to a power source supplying $16.0 \mathrm {~V}$ ? The resistivity of the metal is $1.68 \times 10 ^ { - 8 } \Omega \cdot \mathrm { m }$.
A) $0 \mathrm {~A}$
B) $0 \mathrm {~A}$.
C) $0 \mathrm { nA }$
D) $0 \times 10 ^ { 8 } \mathrm {~A}$

Question

Quizplus · Accepted Answer

The resistance of the wire is:$$R = \rho \frac{L}{A} = \rho \frac{4L}{\pi r^2}$$where $\rho$ is the resistivity, $L$ is the length, $A$ is the cross-sectional area, and $r$ is the radius.Substituting the given values, we get:$$R = (1.68 \times 10^{-8} \Omega \cdot \mathrm{m}) \frac{4(40.0 \mathrm{m})}{\pi (0.05 \times 10^{-3} \mathrm{m})^2} = 1.07 \times 10^3 \Omega$$The current is then:$$I = \frac{V}{R} = \frac{16.0 \mathrm{V}}{1.07 \times 10^3 \Omega} = 14.95 \times 10^{-3} \mathrm{A} \approx 0 \mathrm{A}$$

How Much Current Will Flow Through a 40 0.0 mm0.0 \mathrm {~mm}0.0 mm

How Much Current Will Flow Through a 40 $0.0 \mathrm {~mm}$