If a wire of resistance $R$ is melted and recasted to half of its length,then the new resistance of the wire will be

$A$ conductor has resistance values of $2.71 \ \Omega$ and $3.70 \ \Omega$ at $10^{\circ}C$ and $100^{\circ}C$ respectively. The temperature at which the resistance is $3.26 \ \Omega$ is .......... $^{\circ}C$.

What is the resistance of a wire of length $5 \, m$ and resistivity $1.7 \times 10^{-8} \, \Omega \cdot m$,given the cross-sectional area is a hollow cylinder with outer radius $r_2 = 10 \, cm$ and thickness $5 \, mm$?

The solids which have the negative temperature coefficient of resistance are:

The current flowing through a conductor connected across a source is $2\,A$ and $1.2\,A$ at $0^{\circ}C$ and $100^{\circ}C$ respectively. The current flowing through the conductor at $50^{\circ}C$ will be $......\times 10^2\,mA$.

If the resistance of a conductor is $5\,\Omega$ at $50\,^{\circ}\text{C}$ and $7\,\Omega$ at $100\,^{\circ}\text{C}$,then the mean temperature coefficient of resistance of the material is ............... $^{\circ}\text{C}^{-1}$.