Question

hollow sphere of external and internal diameters
16 cm and 8 cm respectively Find the volume and
the outer surface area of hollow sphere.​

Answer 1

Answer:

Let R and r be the external and internal radii of the hollow sphere.

Let h and r

1

be the height and the radius of the cone to be made.

Hollow sphere

External:

2R=8cm

⇒ R=4cm

Internal

2r=4cm

⇒

r=2cm

Cone

2r

1

=8

⇒

r

1

=4

When the hollow sphere is melted and made into a solid cone, we have

Volume of the cone = Volume of the hollow sphere

⇒

3

1

πr

1

2

h=

3

4

π[R

3

−r

3

]

⇒

3

1

×π×4

2

×h=

3

4

×π×(4

3

−2

3

)

⇒h=

4

64−18

=14

Hence, the height of the cone h=14cm