- #1

fishturtle1

- 394

- 82

## Homework Statement

A 5.00-A current runs through a 12 gauge copper wire (diameter 2.05mm) and through a light bulb. Copper has 8.5 x 10

^{28}free electrons per cubic meter.

c) At what see does a typical electron pass by any given point in the wire?

## Homework Equations

J = nqv

_{d}

## The Attempt at a Solution

The previous parts of the question I solved for current density.

J = 3.105 x 10

^{6}A / m

^{2}

n = 8.5 x 10

^{28}electrons / m

^{3}

v

_{d}= J / n|q|

I substituted all my values in:

v

_{d}= (3.105 x 10

^{6}) / (8.5 x 10

^{28})(1.602 x 10

^{-28})

v

_{d}= (3.105 x 10

^{6}) / 13.167 m/s

v

_{d}= 2.28 x 10

^{5}m/s

the correct answer is v

_{d}= 0.111 mm/s

I'm sorry this is probably an arithmetic error but i can't see what I did wrong