A solid lead ball of radius 6 cm is melted and then drawn into a wire of diameter 0.2 cm.

(b)  288 m

Let h m be the length of wire.
Volume of the lead ball = volume of the wire

$\Rightarrow \frac{4}{3} \pi \times 6^{3}=\pi \times(0.1)^{2} h$

$\Rightarrow h=\frac{4 \times 216}{3 \times 0.01}=28800 \mathrm{~cm}=288 \mathrm{~m}$