Q10 of 44 Page 14

The diameter of a copper sphere is 6cm. The sphere is melted and is drawn into a long wire of uniform circular cross-section. If the length of the wire is 36cm, find its radius [Take π=2.14]

Diameter of a copper sphere = 6 cm


So, Radius of copper sphere = 3cm



=


= 36π cm3


Length of wire = 36cm


Let the radius of wire be R cm


Volume of wire = πR2h


=πR2×36


But the volume of wire = volume of sphere


⇒ 36πR2 = 36π


⇒ R2 = 1


⇒ R = 1cm [taking positive root, because radius can’t be negative]


Hence, the radius of wire is 1cm


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