Question

A hollow sphere with external and internal diameter 8 and 4 respectively is melted.....

Answer 1

External diameter of sphere = 8 cm 

radius, R = 4 cm

Internal diameter of sphere = 4 cm 

radius, r = 2 cm

Diameter of the base of cone = 8 cm 

radius = 4 cm

Now, Volume of the cone = Volume of the material in the sphere

Check this attachment :-)

Hence, the height of the cone = 14 cm