Question

$1c{m}^3$ of copper is drown into a wire $0.2mm$ diameter. Find the length of the wire.

Answer 1

Volume of copper $=1c{m}^3$

Length of wire $=$ x

Radius $=0.1$ mm

Volume of wire $=$ volume of copper

$\Rightarrow \pi r^{2}h=1c{m}^3$

$\Rightarrow \pi \left(\frac{0.1}{10}\right)\left(\frac{0.1}{10}\right)h=1$

$\Rightarrow h=\frac{10\times 10\times 100}{0.7\times 0.1\times \pi }=3183cm$

$\Rightarrow h=31.83m$.