Question

In a hot water heating system, there is a cylindrical pipe of length $28m$ and diameter $5cm$. Find the total radiating surface in the system.

• A. $4.4m^2$
• B. $2.4m^2$
• C. $4.1m^2$
• D. $3.4m^2$

Answer 1

The correct option is A $4.4m^2$

Here, the length, $h$ of the cylindrical pipe$=28m$

Radius $r=\frac{5}{2}cm=\frac{5}{2\times 100}m=\frac{5}{200}m=\frac{1}{40}m$

$\therefore$ Total radiating surface in the system $=$ CSA of the pipe

$=2\pi rh$

$=2\times \frac{22}{7}\times \frac{1}{40}\times 28$

$=\frac{44}{7}\times \frac{1}{40}\times 28m^2$

$=\frac{11}{1}\times \frac{1}{10}\times 4m^2$

$=\frac{44}{10}$

$=4.4m^2$

Hence, area of total radiating surface is $4.4m^2$