$A$ wire of resistance $4 \,\Omega$ is stretched to twice its original length. The resistance of the stretched wire would be ........... $\Omega$.

For metals,is the temperature coefficient of resistivity positive or negative?

$A$ wire $100\,cm$ long and $2.0\,mm$ diameter has a resistance of $0.7\,\Omega$. The electrical resistivity of the material is ...........$ \times 10^{-6}\,\Omega \cdot m$.

What length of the wire of specific resistance $48 \times 10^{-8} \, \Omega \, m$ is needed to make a resistance of $4.2 \, \Omega$ (in $.1$)? (Diameter of wire = $0.4 \, mm$)

The resistance of a conductor at $20\,^{\circ}C$ and $500\,^{\circ}C$ is $20\,\Omega$ and $60\,\Omega$ respectively. At what temperature will the resistance be $25\,\Omega$?

The resistance of a conductor is $5\,\Omega$ at $50\,^{\circ}C$ and $6\,\Omega$ at $100\,^{\circ}C$. Its resistance at $0\,^{\circ}C$ is ................ $\Omega$.