Potential Difference Between Two Points In an Electric Field - Current Density & Resistivity

This physics video tutorial explains how to calculate the potential difference between two points in an electric field on a metallic conductor. It also explains how to calculate the current density given the electric current and the diameter of the material. The current density is equal to the current divided by the cross sectional area. The electric field is equal to the resistivity of the material multiplied by the current density. The potential difference is the product of the electric field and the distance between the two points. This video contains plenty of examples and practice problems.

Electric Current In Circuits:

The Electric Battery:

Ohm's Law Problems:

Resistance and Resistivity:

Resistor Color Code:

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Internal Resistance of a Battery:

Electromotive Force of a Battery:

Drift Velocity and Current Density:

Alternating Current Vs Direct Current:

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Schematic Diagrams & Symbols:

Open, Closed, and Short Circuits:

Resistors In Series:

Resistors In Parallel:

Physics PDF Worksheets:

[the_math_guy]

I have seen E=dV/dr for some cases and
E=-dV/dr during some(while establishing relationship between potential gradient and electric field)
Why is it different?

[theadel]

If the voltage drops as you travel along the direction of conventional current, then how is this issue handled in power lines ?

[atreusshimada]

Hi, can someone help me how to calculate the current carrying of a wire? it says that a current-carrying copper wire has an electric field of 0.560 v/m with a diameter of 0.750 mm. What is the wire's current carrying capacity?