Question

Q3. Define resistances of a conductor and
describe the factors of affecting the
resistance. Also write expression between
resistance and resistiviny.​

Answer 1

Answer:

the opposition offered by the conductor to the flow of current is called resistance (or) it is the ratio of voltage to current

factors affecting:-

1) length of conductor

2) area of conductor

3) material of conductor

R= (rho) l / A

where rho - resistivity

Answer 2

Question:

factors that affect the resistance of a conductor

Answer:

The factors affecting resistivity of a conductor are:

The Material of Wire

The Length of Wire

The Area of Cross Section of Wire

The Temperature of the Wire

Let's define all of them:

The Material of Wire

The resistance of a wire depends on the number of collisions which the electrons moving through it suffer with the other electrons and fixed positive ions of the wire. In different materials, the concentration of electrons and the arrangement of atoms are different, therefore, the resistance of wires of same length, same area of cross section, but of different materials differ depending on their material. Good conductors having higher concentration of free electrons (such as metals) offer less resistance.

The length of wire:

The number of collisions suffered by the moving electrons will be more if they have to travel a longer distance in a wire, therefore, a long wire offers more resistance than a short wire.

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 less resistance.

The temperature of the wire:

If the temperature of wire increases, ions in it vibrate more violently. As a result, the number of collisions increases and hence the resistance of wire increases.