The resistivity of a wire:

$A$ heating element has a resistance of $100\,\Omega$ at room temperature. When it is connected to a supply of $220\,V$,a steady current of $2\,A$ passes through it and the temperature is $500\,^{\circ}C$ higher than room temperature. What is the temperature coefficient of resistance of the heating element?

$A$ wire of a certain material is stretched slowly by $10 \%$. Its new resistance and specific resistance become respectively:

Consider four conducting materials: copper,tungsten,mercury,and aluminium with resistivity $\rho_{C}, \rho_{T}, \rho_{M}$,and $\rho_{A}$ respectively. Then:

At what temperature will the resistance of a copper wire become three times its value at $0^{\circ}C$? (Temperature coefficient of resistance for copper = $4 \times 10^{-3} \,^{\circ}C^{-1}$)

Two wires of same length and thickness having specific resistances $6 \, \Omega \, cm$ and $3 \, \Omega \, cm$ respectively are connected in parallel. The effective resistivity is $\rho \, \Omega \, cm$. The value of $\rho$ to the nearest integer is ..... .