Question

Consider a magnesium wire (σ = 2.2 ✕ 107 Ω−1 · m−1) with a cross-sectional area of 1 mm2 (similar to your connecting wires) and carrying 0.3 amperes of current, which is about what you get in a circuit with a round bulb and two batteries in series. Calculate the strength of the very small electric field required to drive this current through the wire.

Answer 1

Answer: 1.36 x 10^-2 N/C

Explanation:

I/A = σ E

E = I / (A σ)

E = 0.3A / (1x10^-6 m^2 2.2 x10^7/ ohm m)

E = 1.36 x^-2 N/C