(a) An electric iron rated $2\cdot 2\text{ kW}, 220\text{ V}$ is operated at $110\text{ V}$ supply. Find : (i) its resistance, and (ii) heat produced by it in $10$ minutes. OR (b) A current of $4\cdot 0\text{ A}$ flows through a wire of length $1\text{ m}$ and cross-sectional area $1\cdot 0\text{ mm}^2$, when potential difference of $2\text{ V}$ is applied across its ends. Calculate the resistivity of the material of the wire.