Which of the following materials is the best conductor of electricity?

The resistance of a wire of uniform diameter $d$ and length $L$ is $R$. The resistance of another wire of the same material but diameter $2d$ and length $4L$ will be

When the length and area of cross-section both are doubled,then its resistance

Which of the following wires made of the same material will have the highest resistance?

$I-V$ characteristic of a copper wire of length $L$ and area of cross-section $A$ is shown in the figure. The slope of the curve becomes

If a conducting wire of length $L$ is uniformly stretched to double its length, then its conductivity becomes . . . . . . .