Question

A copper sphere of diameter 18 cm is drawn into a wire of diameter 4 mm. Find the length of the wire.

Answer 1

Volume of sphere = $\frac{4}{3}$$\pi r^3$ = $\frac{4}{3}$ $\times$$\frac{22}{7}$ $\times$ $9^3$ $c{m}^3$

Let length of the wire be x cm

Volume of cylinder = $\pi r^{2}l$ = $\pi$ $\times$ ${0.2}^2$$\times$ $x$
Volume of sphere = Volume of cylinder

$\Rightarrow$ $\frac{4}{3}$ $\times$$\pi$$\times$ $9^3$ $c{m}^3$ = $\pi$ $\times$ $2\times {10}^{-}2$ $\times$ $x$
$\Rightarrow$ x =24300 cm = 243 m