Question

A medicine capsule is in the shape of cylinder with two hemispheres stuck to each of its ends (see the given figure). The length of the entire capsule is 14 mm and the diameter of the capsule is 5 mm. Find its surface area. [Use π = `22/7`]

 

Answer 1

It can be observed that

Radius (r) of cylindrical part = Radius (r) of hemispherical part 

= `"Diameter of the capsule"/2`

= `5/2`

= 2.5 mm

Length of cylindrical part (h) = Length of the entire capsule − 2 × r

= 14 − 2 × 2.5

= 9 mm

Surface area of capsule = 2 × CSA of hemispherical part + CSA of cylindrical part

= 2 × 2πr² + 2πrh

`= 4pi(5/2)^2 + 2pi(5/2)(9)`

= 25π + 45π

= 70π mm²

= `70 xx 22/7`

= 220 mm²