Question

What is electrical resistivity? In a series electrical circuit comprising of a resistor having a metallic wire, the ammeter reads 5A. The reading of the ammeter decreases to half when the length of the wire is doubled. Why?

Answer 1

The resistivity of a material is defined as the resistance of a conductor made of that material of unit length and unit cross-sectional area.

It is doubled while V remains unchanged. Hence, the current becomes half.