Question

A hemispherical bowl is made of steel, 0.25 cm thick. The inner radius of the bowlis
5 cm. Find the outer curved surface area of the bowl.
A right circular cylinder just encloses a sphere of
radius r(see Fig. 13.22). Find
(1) surface area of the sphere,
1) curved surface area of the cylinder,
(111) ratio of the areas obtained in (i) and (ii).
132​

Answer 1

Answer:

Inner radius of hemispherical bowl = 5cm

Thickness of the bowl = 0.25 cm

Outer radius of hemispherical bowl = (5+0.25) cm = 5.25 cm

Formula for outer CSA of hemispherical bowl = 2πr2, where r is radius of hemisphere

= 2×(22/7)×(5.25)2 = 173.25

Therefore, the outer curved surface area of the bowl is 173.25 cm2.

Answer 2

surface area of the sphere