Question

What is the cause of resistance?

Answer 1

Resistance - Higher tier. An electric current flows when electrons move through a conductor, such as a metal wire. The moving electrons can collide with the ions in the metal. This makes it more difficult for the current to flow, and causes resistance.

The resistance of a conductor is the obstruction offered by the conductor to the flow of electric current through it.

Resistance (R) of a conductor is defined as the ratio of the potential difference (V) across the ends of the conductor to the current (I) flowing through it i.e.

R=V/l

The S.I unit of resistance is Ohm. Where 1 Ohm= 1volt/1ampere=1V/1A

Thus 1 ohm is the resistance of a conductor through which a current of 1 ampere flows when a potential difference of 1 volt is applied across the ends of the conductor.



cause of the resistance of a wire: Resistance of a given conducting wire is due to the collisions of free electrons with each other, the ions or atoms of the conductor and the walls of the conductor during their drift towards the positive end of the conductor which in turn depends upon the arrangements of atoms in the conducting material as well as on the length and thickness of the conducting wire.