- #1
david12445
- 11
- 1
Homework Statement
The terminals of a 0.70 Vwatch battery are connected by a 70.0-m-long gold wire with a diameter of 0.100 mm.
What is the current in the wire?
Homework Equations
V = IR
R = pL/a
The Attempt at a Solution
I try to find resistance first, resistivity of gold is 2.2 * 10 ^-8
Area of the wire is a = pi * r ^ 2
r = ( 0.1 * 10^-3 ) /2
So I found a = 7.85 * 10^-9
Then,
R = 2.2 * 10^-8 * 70 / (7.85 * 10^-9) = 196.1
I plug this into V/R = I, .70/196.1 = .00357 = 3.57 mA, but this answer ends up being wrong. Any help on where I went wrong would be appreciated, thanks.