# The rate at which the energy in the wire is transformed into kinetic

1. Apr 13, 2013

### Pruddy

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

A potential difference of 50 mV is maintained between the ends of a 9.70 m length of wire whose cross section area is 25.0mm^2. The conductivity of the wire is 6.80 x 10^6 (ohm.m)^-1. Determine the rate at which the energy in the wire is transformed into kinetic to thermal energy.

2. Relevant equations
P = v^2/R

ρ = 1/c

R = ρ (L/A)

Where ρ = resistivity
c = conductivity
A = area
L = length
R = Resistance
V = Voltage
P = power

3. The attempt at a solution

ρ = 1/6.80 x 10^6 = 1.471 x 10^(-7)

R = 1.471 x 10^(-7) * ( 9.70/0.000025 )
= 0.0570748
P = (50 x 10^-3)/0.0570748
= 0.0438021
= 4.38 x 10^(-2) W

This is my complete work. I think my workings are correct but I am not to sure of the answer. I will be glad if anyone can help.
1. The problem statement, all variables and given/known data

2. Relevant equations

3. The attempt at a solution
1. The problem statement, all variables and given/known data

2. Relevant equations

3. The attempt at a solution

2. Apr 13, 2013

### barryj

You have an amazing calculator

P = (50 x 10^-3)/0.0570748
= 0.0438021

I think you got the correct answer

3. Apr 13, 2013

### Pruddy

Thank you.

4. Apr 14, 2013

### Pruddy

My professor says my answer is wrong.

5. Apr 14, 2013