What is the field strength and when does a situation like this occur?

[aps0324]

Please help me with the following:

What is the field strength needed to achieve a current density of 5 x10^4 [Am^-2] in a conductor of resistivity 5 x 10^-8 [Ω m]

The answer I got was 2.5 x 10^-3 N C^-1

using the equation J = σ E

But then I was wondering when a situation like this occurs and this i do not know.

Thank you for any help

 

[Bob S]

Thank you for using mks units. because an ohm is one volt per amp, we can multiply 50,000 amps per square meter and 5 x 10^-8 ohm meters (pure copper is 1.72 x 10^-8) and get 0.0025 volts per meter. Suppose 100 amps is run in a conductor 0.01 m by 0.01 m. The resistance would be 5 x 10^-4 ohms per meter. The voltage drop would be 0.05 volts per meter, and the power dissipation would be 5 watts per meter.

 

[charng]

.

The field strength needed to achieve a current density of 5 x 10^4 [Am^-2] in a conductor of resistivity 5 x 10^-8 [Ω m] is indeed 2.5 x 10^-3 N C^-1. This value can be derived from the equation J = σ E, where J is the current density, σ is the conductivity (inverse of resistivity), and E is the electric field strength.

A situation like this occurs when there is a need for a high current density in a conductor. This may happen in applications such as high voltage power transmission, where a large amount of current needs to be carried through a conductor to deliver electricity over long distances. Another example is in electrical motors, where a strong electric field is required to generate a high current density to power the motor and produce motion. Additionally, this situation may also occur in research or experimental settings where high current densities are needed for specific experiments or studies.