Question

Which of the following would increase the conductivity of a connecting wire?
increase the diameter of the wire,
increase the length of the wire,
decrease the temperature of the wire,
or switch from steel wire to gold wire?

Answer 1

Answer : On increasing the length of the wire, the conductivity would increase.

Explanation :

We know the relation between resistivity and conductivity is given as :

$\sigma=\dfrac{1}{\rho}$

Where,

$\sigma$ is the conductivity

$\rho$ is the resistivity of the wire

Also, $\rho=R\dfrac{A}{l}$

A is the area of cross section

l is the length of the wire.

So, conductivity becomes :

$\sigma=\dfrac{l}{R\times A}$

So, conductivity of a wire is directly proportional to the length of the wire and inversely proportional to its area.

On increasing the length of the wire, the conductivity of wire also increases.        

Hence, the correct option is (b) " increase the length of the wire ".

Answer 2

Answer:

Increase the diameter of the wire and switch from steel wire to gold wire

Explanation: