Solution

During an experiment, a copper wire of $50\,\mathrm{m}$ long and $150\,\mu\mathrm{m}$ thick is hung vertically. Then a current of $1\,\mathrm{A}$ is passed across its ends for $50\,\mathrm{s}$. Find the resistance of the wire and the heat dissipated during this process. [Resistivity of copper is $1.69 \times 10^{-8}\,\Omega\cdot\mathrm{m}$.]