The diameter of a copper sphere is 6 cm. The sphere is melted and is drawn into a long wire of uniform circular cross-section. If the length of the wire is 36 cm, then its radius is–

Explanation

Let the radius of sphere = R radius of long wire = r length of the wire = h According of the question- 2R = 6cm R = 3 cm h = 36 cm Volume of the sphere = volume of the wire $$ \frac{4}{3} \times \pi \times 3 \times 3 \times 3 = \pi \times r^2 \times 36 $$ [<mark>r = 1 cm</mark>] Hence, option (e) will be the right answer.