What Are the Drift Speed and Current Density in Copper and Aluminum Wires?

In summary, the conversation discusses the relationship between the diameter and density of conduction electrons in copper and aluminum wires, and how it affects the drift speed and current density in each wire. The equations I=nAqVd and J=nqVd are mentioned as tools for determining these values, but it is noted that without knowing the specific values for current and cross sectional area, only ratios can be determined. The need for more information and the importance of sharing results and methods for checking accuracy are also highlighted.
  • #1
lemaire
16
0

Homework Statement



A piece of copper wire joins a piece of aluminum wire whose diameter is five times that of the copper. The same current flows in both wires. The density of conduction electrons in copper is 1.1 [tex]\times[/tex] 1029 m-3 in aluminum it is 2.1[tex]\times[/tex]1029 m-3.
what is the drift speed and current density in each?

Homework Equations



I = nAqVd
J = nqVd

The Attempt at a Solution


the cross sectional area is unknown and the current is unknown. i think the drift speed of one will be a function of the other. I have an expression but since i am using a web software, i would like to see if someone else gets the same expression as i do.
 
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  • #2
1. You are correct - the values of the drift speeds and current densities can not be determined with the info provided. You can only determine the ratios.

2. You have to tell us what answers you get (and how you got them), and we will let you know if you've made a mistake (and where you made it). It doesn't work the other way round.
 

Related to What Are the Drift Speed and Current Density in Copper and Aluminum Wires?

What is drift speed?

Drift speed is the average velocity at which charged particles, such as electrons, move in an electric field. It is typically measured in meters per second (m/s).

How is drift speed related to current?

Drift speed is directly proportional to the current in a circuit. This means that as the current increases, the drift speed of the charged particles also increases.

What factors affect drift speed?

The drift speed of charged particles is affected by the strength of the electric field, the material through which the particles are moving, and the density of the particles.

What is current density?

Current density is a measure of the amount of current flowing through a given area. It is calculated by dividing the current by the cross-sectional area of the material in which the current is flowing and is typically expressed in amperes per square meter (A/m²).

How is current density related to drift speed?

Current density is directly proportional to drift speed. This means that as the drift speed of charged particles increases, the current density also increases.

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