The lead wires should have

The resistance of a rectangular block of copper of dimensions $2 \,mm \times 2 \,mm \times 5 \,m$ between two square faces is $0.02 \,\Omega$. What is the resistivity of copper?

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

Two different conductors have the same resistance at $0\,^{\circ}C.$ It is found that the resistance of the first conductor at $t_1\,^{\circ}C$ is equal to the resistance of the second conductor at $t_2\,^{\circ}C.$ The ratio of the temperature coefficients of resistance of the conductors,$\frac{\alpha_1}{\alpha_2}$ is

The resistance of the filament of an 'incandescent' bulb increases with an increase in temperature. If $R_{100}$,$R_{60}$,and $R_{40}$ are the resistances of $100 \ W$,$60 \ W$,and $40 \ W$ bulbs at room temperature,respectively,then:

$A$ cylindrical wire $P$ has resistance $10 \ \Omega$. $A$ second wire $Q$ has length and diameter half that of $P$. If the material of both the wires is same,then the resistance of wire $Q$ is (in $Omega$)