What Is the Average Velocity of Electrons in a Copper Wire Carrying 1.0A?

In summary, copper has approximately 10^29 free electrons per cubic meter and a resistivity of 1.68 * 10^-8 ohms meter. The approximate average velocity of electrons in a 1.0 mm radius wire carrying 1.0A is 2 * 10^-5 m/s.
  • #1
eno
7
0
Copper has approximately 10^29 free electrons per cubic meter. What is the approximate average velocity of electons in a 1.0 mm radius wire carrying 1.0A?

resisivity, p of copper = 1.68 * 10^-8 ohms meter

The answer in the book apparently is 2 * 10^-5 m/s.

Please help by showing all your work. Your attempts will be greatly appreciated.
 
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  • #2
the answer is 2 * 10^-5 m/s.
please read this before posting...
https://www.physicsforums.com/showthread.php?t=28 :-p
 
  • #3
i have tried it many times and it did not reach tat ans.
 
  • #4
the current [itex] I [/itex] is equals to free electrons density [itex] \rho [/itex] times charge per electrons [itex] e [/itex] times drift velocity [itex] v [/itex] times cross section area [itex] A [/itex]
[tex] I=\rho e v A [/tex]
ring the bell?
since you have everything except v, this is one equation with one unknown... solving it is straight forward...
you must be careful on the unit conversion, it is a little bit tricky...
the area is not given directly, but you have radii, the area shold be piece of cake
charge of electron is on the back of your textbook... if not, look it up on internet
show me your calculation ...
 
  • #5
Within 1 sec, e drifted for length L

L = v * 1 sec = v

total e drifted within 1 sec is 1 Ampere.

1.0 A = 6.24*10^18 e = 10^29 * v * (π * (0.001)^2)

v = 2 * 10^-6 m/s

therefore, does not match with the ans in the book.
 
  • #6
Within 1 sec, e drifted for length L

L = v * 1 sec = v

total e drifted within 1 sec is 1 Ampere.

1.0 A = 6.24*10^18 e = 10^29 * v * (π * (0.001)^2)

v = 2 * 10^-6 m/s

therefore, does not match with the ans in the book.

what the hack are you doing here?
 
  • #7
[tex] I=\rho e v A [/tex]
[tex] \rho [/tex] is the free electronss density
[tex] e [/tex] is the charge per electron...
[tex] A [/tex] is the cross section area
[tex] I [/tex] is the current
plug in all number and solve for v...
 
  • #8
it appears that I have punched in the wrong notation the whole time. ths for ur help.
 
  • #9
I don't know why, but i just can't seem to get the answer :(

the formula i use is

I = NaQv

so V = I / NAQ

A (cross sectional area) = (0.001)^2 multiplied by Pi
Q = 1.6 * 10^-19
N= 10^29
I = 1

is this right so far?

Regards,
Mo
 
  • #10
Yes,it's identical to what the OP did.You should get the same answer.[tex] 2\times 10^{-5}m \ s^{-1} [/tex]

Daniel.
 

FAQ: What Is the Average Velocity of Electrons in a Copper Wire Carrying 1.0A?

What is the difference between AC and DC electricity?

AC (alternating current) electricity is when the direction of the electric current changes periodically, while DC (direct current) electricity is when the current flows in one direction continuously. AC is typically used for long-distance power transmission, while DC is often used for smaller electronic devices.

How is electric resistance different from electric conductance?

Electric resistance is a measure of how much a material resists the flow of electric current, while electric conductance is a measure of how easily electric current can flow through a material. In other words, resistance is an obstruction to current flow, while conductance is a measure of the ease of current flow.

What is the relationship between voltage, current, and resistance?

Ohm's law states that the current (I) flowing through a conductor is directly proportional to the voltage (V) applied to it, and inversely proportional to the resistance (R) of the conductor. This can be expressed as the equation V=IR.

How does an electric circuit work?

An electric circuit is a closed loop through which electric current can flow. It typically consists of a power source (such as a battery), wires to carry the current, and a load (such as a light bulb) that uses the current to do work. The current flows from the power source, through the load, and back to the power source in a continuous loop.

What are the different types of electric circuits?

There are three main types of electric circuits: series, parallel, and series-parallel. In a series circuit, all components are connected in a single loop, so the current is the same at any point in the circuit. In a parallel circuit, components are connected in multiple branches, and the current splits between them. A series-parallel circuit combines aspects of both series and parallel circuits, with some components connected in series and others in parallel.

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