Physics

Problem

A solid cylindrical copper rod of length

50\,\text{cm}

and radius

3\,\text{mm}

is drawn into a thinner wire of radius

2\,\text{mm}

with no change in volume. What is the ratio of the resistance of the new wire to that of the original rod? a)

\approx 3.4\text{ times}

\approx 5\text{ times}

\approx 2.25\text{ times}

\dfrac{1}{5}\text{ times}