The radius of a sphere is 6 cm. It is melted and drawn into

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The radius of a sphere is 6 cm. It is melted and drawn into

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The radius of a sphere is 6 cm. It is melted and drawn into a wire of radius 0.2 cm. The length of the wire is

1. 81 metre
2. 80 metre
3. 75 metre
4. 72 metre

Correct Option: D

In both cases, volume will remain same.
Volume of sphere = 4 πr³
3

= 4 π(6)³
3

= 288π cu. cm.
If the length of wire be h cm., then
⇒ πR²h = 288π
⇒ (0.2)² × h = 288
⇒ h = 288 = 7200 cm.
0.04

= 72 metre