Question

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

• A. $40073.98c{m}^2$
• B. $300039.28c{m}^2$
• C. $40009.28c{m}^2$
• D. $44039.28c{m}^2$

Answer 1

Answer: (D)

$44039.28c{m}^2$

Diameter = 5 cm

Radius = Diameter $÷2=5cm÷2=2.5cm$

length of pipe $=28m=2800cm$

Total Radiating Surface of pipe = Curved surface area + 2 $\times$ Area of circular crossection

$=2\pi rh+2\pi r^2=2\pi r(h+r)=2\times \frac{22}{7}\times 2.5(2800+2.5)=44039.28c{m}^2$