Question

Two copper wires are of the same length, but one is thicker than the other.

(i) Which wire will have more resistance?

(ii) Which wire will have more specific resistance?

Answer 1

1. We know that Resistance $R=\rho \frac{l}{A}$

Where,

$$\begin{gathered} R=Resis\tan ceofcopperwire. \\ l=Lengthofwire. \\ A=Cross-sectionalarea. \\ \rho =Specificresis\tan ceofcopperwire. \end{gathered}$$

2. (i) For the same length of wire resistance is inversely proportional to the cross-sectional area of the wire.

So, the wire with less thickness has more resistance.

3. (ii) Specific resistance of a wire depends on the material of the wire at a given temperature. Since, both the wires are of copper, so the specific resistance remains the same.