# Determining current and drift speed

1. Mar 5, 2008

### octahedron

[SOLVED] Determining current and drift speed

1. The problem statement, all variables and given/known data

The two wires in the above figure are made of the same material. What are the current and the electron drift speed in the 2.0mm-diameter segment of the wire.

2. Relevant equations

I = J/A; J = n*e*v_d where n is the density of the conductor in m^-3 and v_d is drift velocity.

3. The attempt at a solution

I was able to find the density of the conductor:

$$n = \frac{I_{1}}{(Aev_{d_1})} = 2*10^{28}$$

Also, I reached to this relationship between $$I_2$$ and $$v_{d_2}$$:

$$I_{2} = 20000v_{d_2}$$

What to do next? Appreciate any pointers, and thanks in advance.

2. Mar 6, 2008

### octahedron

Ah, again, I_2 = I_1. *smacks head* This solves the problem.