Consider a straight lenght of copper wire of diameter d=2 mm and Lenght = 10 m. The resistivity of copper is p= 1.68x10^-8 ohms. If the current in the wire is 1.5 A, then what is the putential difference across it?

The potential difference across the wire is 0.08V.

Explanation:

The relationship between voltage , resistance , and current is

,

Now, the resistance can be expressed as

where is the resistivity, is the length, and is the cross sectional area of the wire.

The cross sectional area of 2mm diameter wire is

,

therefore, the resistance is

.

Now, we are told that the current through the wire is 1.5A; therefore the potential difference across it will be

To conclude, the potential difference across the wire is 0.08V.

the answer is neither ball has a charge.

because if they were both positively charged, they will repel each other.

if they were positively and negatively charged, they will seek.