Question

List the factors on which the resistance of a conductor in the shape of a wire depends.

Answer 1

HintThe resistance of a conductor is the property by a virtue of which it opposes the flow of charge through it. It is equal to the ratio of the potential difference applied across the conductor to the current flowing through it. As it is a physical quantity of a conductor it must depend on the physical as well as the structural characteristics of the conductor.

 Complete step-by-step solution:
The materials which can conduct electric current in the form of energy fairly well are called conductors. Example: Metals
Factors on which the resistance of a conductor of the shape of the wire depends:
The first factor is that the resistance of the straight conductor is directly proportional to its length.
$R \propto L$..........… (1)

The second factor is that the resistance of a straight conductor is inversely proportional to t its area of cross section.
$R \propto \dfrac{l}{A}$..........…… (2)
A = Area of the cross-section
L = length
From (1) and (2)
$R \propto \dfrac{l}{A}$
Therefore, $\rho \dfrac{l}{A}$
$\rho $= constant which is called resistivity or the specific resistance of the material of the conductor.

The resistance of the conductor can also be dependent upon the temperature of the conductor and the nature of material used.

Note:- Generally, the resistance of the wire is depend on the three factors:
1. Nature of material of the conductor
2. Length
3. Area of cross section
It can also depend on the physical conditions like temperature and pressure but it is independent of its shape and size. When the frequency of the supply increases then temperature would also increase, and if the temperature is increased then resistance of the wire also increases.