The conductivity of a conductor decreases with temperature because,on heating:

$A$ silver wire has a resistance of $2.1\; \Omega$ at $27.5^{\circ} C$ and a resistance of $2.7\; \Omega$ at $100^{\circ} C$. Determine the temperature coefficient of resistivity of silver.

Two wires of the same material are given. The first wire is twice as long as the second and has twice the diameter of the second. The resistance of the first will be

$A$ wire of resistance $5 \Omega$ is stretched so that its new length is $3$ times its original length. What is the resistance of the new wire?

An electric wire of length $l$ and area of cross-section $a$ has a resistance $R \ \Omega$. Another wire of the same material having the same length and area of cross-section $4a$ has a resistance of:

For wiring in the home,one uses $Cu$ wires or $Al$ wires. What considerations are involved in this?