Question

A long copper wire with radius of 1.0 mm carries a uniform surface charge density of 5.0 x 10^-6 C/m².

a. Find the total charge in a 1.0-meter-long section of the wire.

b.. Find the magnitude of the electric field at a distance of 15 cm from the wire.

Answer 1

a. The total charge is

$$Q=qA=q(2\pi rL)=3.14·10^{-8}\text{ C}.$$

b. The electric field is

$$E=\frac{Q/L}{2\pi\epsilon_0R}=3763\text{ V/m}.$$