Problem

An aluminium wire carrying a current has diameter

0.84\,\mathrm{mm}

. The electric field in the wire is

0.49\,\mathrm{V/m}

. What is Specific resistance of aluminium is

2.75 \times 10^{-8}\,\Omega \cdot \mathrm{m}

. a. the current carried by the wire? b. the potential difference between two points in the wire

12.0 \text{ m}

apart? c. the resistance of a

12.0 \text{ m}

length of this wire?