Question

1.A copper cylindrical wire which has a radius of 1.2 * 10 ^-3m carries a constant current of 6.0 A. Assume each copper atom contributes one free electron. The density of copper is 8.93 g/cm³. Calculate the following:

a.Drift velocity, v_D, (m/s)

b.Resistance (Ω) of a 2 meter segment of this wire at room temperature

You will need to look up the following:
1. molar mass of copper, 2. resistivity of copper @ room temp, 3. Avogadro’s number

Answer 1

a)

Drift velocity

Vd = I/nAq

Vd = 6/(8930x6x10^23 x1.6x10^-19)

Vd = 0.000000006 m/sec

b)

resistivity = 1.7 x 10^-8

R = resistivity x L/A

R = 0.00751565 ohm