Question

A cubic cm of gold is drawn into a wire $0.1mm$ in diameter, find the length of the wire.

Answer 1

Volume of cube $=$ Volume of wire $\Rightarrow 1{cm}^3=\pi r^{2}h$

$\Rightarrow \frac{22}{7}\times {\left(0.05\right)}^2\times h={(1\times 10)}^3{mm}^3=1000{mm}^3\Rightarrow h=\frac{1000\times 7}{22\times 0.0025}=12727.73mm$

$\Rightarrow h=\frac{127272.73}{1000}m[\because 1mm=\frac{1}{1000}m]$

$\Rightarrow h=127.3m$, $\therefore$ Length of wire $=127.3$m