The conductivity of a superconductor is

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

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:

The resistance of a coil is $4.2\, \Omega$ at $100\,^{\circ}C$ and the temperature coefficient of resistance of its material is $0.004\,^{\circ}C^{-1}$. Its resistance at $0\,^{\circ}C$ is ............. $\Omega$.

As the temperature of a conductor increases,its resistivity and conductivity change. The ratio of resistivity to conductivity

$A$ negligibly small current is passed through a wire of length $15 \; m$ and uniform cross-section $6.0 \times 10^{-7} \; m^{2},$ and its resistance is measured to be $5.0 \; \Omega .$ What is the resistivity of the material at the temperature of the experiment?