A solid copper sphere of radius 9 cm is hammered and moulded into a wire of radius 2 cm. What is the length of this wire?
Answer & explanation
Correct answer: option 4
The radius of the sphere = 9 cm
The radius of the wire = 2 cm.
Volume of the wire = π × 22 × a
Volume of the sphere =\(\frac{4}{3}\) πR3 = \(\frac{4}{3}\) π(9)3
Let the length of the wire be a.
According to the question,
π × 22 × a = \(\frac{4}{3}\) π(9)3
= a = 243