Question

XWhy is resistanceproduced in anelectrical circuit?How is resistancemeasured?

Answer 1

Resistance is a measure of the opposition to the flow of current in an electrical circuit.

An electric current flows when electrons move through a conductor. The moving electrons collide with the electrons present in the metal. This makes it more difficult for the current to flow and causes resistance.

According to Ohm's law,

`V\propto I`

Here, V is the potential difference (voltage) and I is the current flowing in the circuit.

Removing the proportionality will give a constant as,

`V=RI`

Here, R is the resistance. Therefore,

`R=(V)/(I)`

It is measured in ohms (Ω).

Higher the current, lower will be the resistance and vice-versa.

The resistance of the given material is,

`\begin{gathered} R\propto L \\ R\propto(1)/(A) \end{gathered}`

Therefore,

`R=\rho(L)/(A)`

Here, L is the length of the conductor, A is the area of the conductor and ρ is the resistivity of the conductor.