If a conducting wire of length $L$ is uniformly stretched to double its length, then its conductivity becomes . . . . . . .

The specific resistance (resistivity) of manganin is $50 \times 10^{-8} \, \Omega \cdot m$. The resistance of a cube of length $50 \, cm$ will be:

Describe the effect of temperature on the electrical resistance of metals and semiconductors.

The resistance of a $5\, cm$ long wire is $10\, \Omega$. It is uniformly stretched so that its length becomes $20\, cm$. The resistance of the wire is ............. $\Omega$.

The resistance of a wire is $20 \, \Omega$. It is stretched such that its length becomes three times its original length. The new resistance of the wire will be ............. $ \Omega$.

Conductivity increases in the order of