Deriving Units for Current Density - J=I/A Length

In summary, current density is a physical quantity represented by the symbol J and measured in A/m^2, which describes the amount of electric current flowing through a given area. It is calculated by dividing the electric current by the cross-sectional area, with units of A/m^2 derived from the units for electric current and area. Measuring current density is important for understanding the distribution of electric current, and it is related to Ohm's law through the equation J = σE.
  • #1
AGGENGR
20
0
Just trying to derive the units for current density but i keep getting A*m rather than A/m^2.

J = I/A

A length derivation would help.
 
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  • #2
What are the units of I and A? ...
 
  • #3
Units of A: C/S
Units of I: A
 
  • #4
How do you get A*m? Where does that come from?

Be careful with the letter A here, it can represent Amperes (as unit) and an area (as symbol).
 
  • #5
Ok i actually see what i was doing wrong. Just a bad algebra error. Thanks!
 

1. What is current density?

Current density is a physical quantity that describes the amount of electric current flowing through a given area. It is represented by the symbol J and is measured in units of amperes per square meter (A/m^2).

2. How is current density calculated?

Current density is calculated by dividing the electric current (I) by the cross-sectional area (A) through which it is flowing. This can be expressed mathematically as J = I/A.

3. What are the units for current density?

The units for current density are amperes per square meter (A/m^2). This is derived from the units for electric current (amperes) and the units for area (square meters).

4. Why is it important to measure current density?

Measuring current density is important because it allows us to understand the distribution of electric current within a given area. This information is crucial in many fields, including electrical engineering, physics, and materials science.

5. How does current density relate to Ohm's law?

According to Ohm's law, the current through a conductor is directly proportional to the voltage and inversely proportional to the resistance. Current density is related to this by the equation J = σE, where σ is the electrical conductivity and E is the electric field strength. This shows that current density is dependent on the electric field, which is related to the voltage and resistance through Ohm's law.

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