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?

Question

Question

This question was previously asked in

SSC CGL 2022 Tier-I Official Paper (Held On : 03 Dec 2022 Shift 3)

Answer 1

Given:

A solid copper sphere of radius 9 cm is hammered and moulded into a wire of radius 2 cm.

Concept used:

1. Volume of a cylinder = πR²H (r = Radius of the base, h = height)

2. Volume of a sphere = \({4\pi R^3 \over 3}\) (R is the radius of the sphere)

3. Volume of the sphere = Volume of the wire

Calculation:

Volume of the sphere = (4π × 9³)/3 cm³

Let the length of the wire be L.

According to the question,

π × 2² × L = (4π × 93)/3

⇒ L = 243

∴ The length of the wire is 243 cm.