Question

What is the resistance of a connecting wire?

Answer 1

Hint: The wire we use provides resistance. The thickness and the length of wires is adjusted such that it can sustain the current and potential difference across it. We will answer this question by 1st knowing what electrical resistance is.

Complete answer:
Electrical resistance is defined as a measure of opposition to current flow in an electrical circuit. It’s SI unit is ohms.Electrical resistance is given by:
\[R = \dfrac{l}{A}\rho \]
where, $R$=resistance of wire, $L$= length or wire, $A$= area of cross section and \[\rho \]=resistivity of wire.
This resistance of wire is because of the collision of free electrons in a conductor while changing their position. The resistance of conducting wire depends on following factors:
-Length of material used
-Area of cross-section of wire
-Temperature

Additional information:
The resistance offered by the wire can also be written in terms of potential difference and current passing through it as: \[R = \dfrac{V}{I}\]ohms. Where V= potential difference across the wire and I is the current passing through it. We can say \[R = \dfrac{V}{I}\] using ohm’s law which states that potential difference across the ends of a connecting wire is directly proportional to the current passing through it.

Note: Resistance is directly proportional to length of conductor, inversely proportional to area of cross section of wire and directly proportional to temperature.Conductors have very low resistance , insulators have high resistance and semiconductors like alloys have comparatively low resistance. It is independent of resistivity.