A metallic spherical shell of internal and external diameters 4 cm and 8 cm, respectively is melted and recast into the form a cone of base diameter 8 cm. The height of the cone is
Volume of spherical shell = Volume of cone recast by melting [1]
For Spherical Shell,
Internal diameter, d1 = 4 cm
Internal radius, r1 = 2 cm
[ as radius = 1/2 diameter]
External diameter, d2 = 8 cm
External radius, r2 = 4 cm
Now,
As volume of spherical shell
where r1 and r2 are internal and external radii respectively.
volume of given shell
Using [1] we have
Volume of cone = 224π /3 cm3
For cone,
Base diameter = 8 cm
Base radius, r = 4 cm
[ as radius = 1/2 diameter]
Let Height of cone be 'h'.
As,
volume of cone =
where r = Base radius and h = height of cone
Volume of given cone
⇒ 16h = 224
h = 14 cm
So, Height of cone is 14 cm.