Question

A big spherical ball of radius 4 cm is completely melted to form small spherical balls of radius 2 cm each, then find the number of small spherical balls?
1. 64
2. 16
3. 8
4. 32

Answer 1

Correct Answer - Option 3 : 8

Given:

Radius of big spherical ball = 4 cm

Radius of small spherical ball = 2 cm

Formula Used:

Volume of sphere = 4/3πr³,  here r = radius

Number of balls = Volume of a big sphere/Volume of a small sphere

Calculation:

Let n be the number of small spherical balls

Volume of big spherical ball = n × Volume of a small spherical ball

4/3π(4 cm)³ = n × 4/3π(2 cm)³ 

⇒ 8n = 64

⇒ n = 64/8 

⇒ n = 8

∴ 8 small spherical balls are formed from a big spherical ball.