A cylindrical nichrome wire of length and diameter has resistivity at

PHYSICS · Subjective · A Level · Physics · Electricity · Electricity

Problem

A cylindrical nichrome wire of length

2.0\,\text{m}

and diameter

1.2\,\text{mm}

has resistivity

1.10\times10^{-6}\,\Omega\,\text{m}

20^{\circ}\text{C}

. The wire is connected to a d.c. source that sends a steady current of

0.50\,\text{A}

through it. (a) Calculate the resistance of the wire at

20^{\circ}\text{C}

. (b) Determine the potential difference applied across the wire. (c) If the same set-up is adjusted so that the current becomes

0.20\,\text{A}

, what must be the new potential difference across the wire, assuming its temperature is still

20^{\circ}\text{C}