Question

The number of solid spheres, each of diameter 6 cm, that can be made by melting a solid metal cylinder of height 45 cm and diameter 4 cm, is

(a) 2 (b) 4 (c) 5 (d) 6

Answer 1

D=6 cm r=3 cm

H=45 cm r=2cm

Let no. of sphere be 'n'

Vol. of cylinder = n x Vol of 1 sphere

$\pi \times R^2\times H=n\times \frac{4}{3}\pi r3$

$\pi \times 2\times 2\times 45=n\times \frac{4}{3}\pi r3$

$180=n\times \frac{4}{3}\times 27$

$\frac{180}{36}=n$

Therefore, n = 5 sphere