State the factors affecting the resistance of a conductor.

Explanation

The factors affecting the resistance of a conductor are:
(i) The material of conductor : The resistance of a conductor depends on the number of collisions which the moving electrons suffer with the other electrons and fixed positive ions of the conductor. In different materials the concentration of electrons and the arrangement of atoms are different therefore the resistance of conductor of same length, same area of cross section but of different materials differ.
(ii) Length of wire : The number of collisions suffered by the moving electrons will be more if they have to travel a longer distance in conductor, Therefore, a long wire offers more resistance than a short wire.
(iii) The area of cross section of wire: In a thick wire, electrons get a larger area of cross section to flow as compared to a thin wire, therefore, a thick wire offers a less resistance.
(iv) The temperature of the wire: If the temperature of the conductor increases, ions in it vibrate more evidently. As a result, the number of collisions increases and hence the resistance of conductor increases (i.e. the resistance of a conductor increases with the increase of its temperature).