Question

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

• A. $4m^2$
• B. $6.2m^2$
• C. $6m^2$
• D. $4.4m^2$

Answer 1

The correct option is D $4.4m^2$

Diameter of the pipe d = 5 cm = 0.05 m
$Radiusr=\frac{d}{2}=\frac{0.05}{2}m$
Length of the pipe h = 28 m
Total radiating surface = 2 $\pi$ r h
$=2\times \frac{22}{7}\times \frac{0.05}{2}\times 28m^2=4.4m^2$