Question

A medicine capsule is in the shape of a cylinder with two hemispheres stuck to each of its ends. The length of the entire capsule is $14mm$ and the diameter of the capsule is $5mm$. Find its surface area.

Answer 1

It can be observed that

Radius $\left(r\right)$ of cylindrical part $=$ Radius$\left(r\right)$ of hemispherical part = $\frac{5}{2}mm$

Length of cylindrical part $\left(h\right)=$Length of the entire capsule$-(2\times r$)

$=14-5=9cm$

Surface area of capsule

$=2\times$ CSA of hemispherical part $+$ CSA of cylindrical part
$=2\times 2\pi r^2+2\pi rh=4\pi {\left(\frac{5}{2}\right)}^2+2\pi \left(\frac{5}{2}\right)\times 9=25\pi +45\pi =70\pi =70\times \frac{22}{7}=220m{m}^2$