The plot of current \(I~\text{(A)}\) flowing through a metallic conductor versus the applied voltage \(V~\text{(volt)}\) across the ends of a conductor is:

1.		2.
3.		4.

Which of the following graph represents the variation of resistivity ($\rho$) with temperature (\(T\)) for copper?

1.		2.
3.		4.

Two solid conductors are made up of the same material and have the same length and the same resistance. One of them has a circular cross-section of area $A_1$ and the other one has a square cross-section of area $A_2$. The ratio $A_1/A_2$ is:

Two metal wires of identical dimensions are connected in series. If ${\mathrm{}}_{}$\(\sigma_1\) $\mathrm{and}$ \(\sigma_2\) are the conductivities of the metal wires respectively, the effective conductivity of the combination is:

A wire of resistance \(4~\Omega\) is stretched to twice its original length. The resistance of a stretched wire would be:
1. \(4~\Omega\)
2. \(8~\Omega\)
3. \(16~\Omega\)
4. \(2~\Omega\)

A 6-volt battery is connected to the terminals of a three-metre-long wire of uniform thickness and resistance of 100 ohms. The difference of potential between two points on the wire separated by a distance of 50 cm will be:

1. 3 V

2. 1 V

3. 1.5 V

4. 2 V