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 ............... $^{\circ}\text{C}^{-1}$.

The specific resistance of a wire is $\rho$,its volume is $3\,m^3$ and its resistance is $3\,\Omega$. Then its length will be:

Two wires are made of the same material. The length and diameter of the second wire are both double those of the first wire. What will be the resistance of the first wire compared to the second wire?

At room temperature $(27^\circ \text{C})$ the resistance of a heating element is $100 \ \Omega$. What is the temperature of the element if the resistance is found to be $137 \ \Omega$,given that the temperature coefficient of the material of the resistor is $1.35 \times 10^{-4} \ ^\circ \text{C}^{-1}$ (in $^\circ \text{C}$)?

The length of the wire is doubled. Its conductance will be

The length and area of cross-section of a copper wire are respectively $30 \ m$ and $6 \times 10^{-7} \ m^2$. If the resistivity of copper is $1.7 \times 10^{-8} \ \Omega \ m$,then the resistance of the wire is (in $Omega$)