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$.

The resistance of a wire at $300 \, K$ is found to be $0.3 \, \Omega$. If the temperature coefficient of resistance of the wire is $1.5 \times 10^{-3} \, K^{-1}$, the temperature at which the resistance becomes $0.6 \, \Omega$ is: (in $K$)

Two wires $A$ and $B$ of the same material and same mass have radii $2r$ and $r$,respectively. If the resistance of wire $A$ is $34\,\Omega$,then the resistance of wire $B$ will be ............ $\Omega$.

$A$ cell of $emf$ $E$ and internal resistance $r$ is connected across an external resistance $R$. Plot a graph showing the variation of potential difference $(V)$ across $R$ versus $R$.

$A$ wire $100\,cm$ long and $2.0\,mm$ diameter has a resistance of $0.7\,\Omega$. The electrical resistivity of the material is ...........$ \times 10^{-6}\,\Omega \cdot m$.

If the length of a wire is increased by $10\%$ by stretching it,the percentage increase in its resistance is ..............$\%$