[amp_mcq option1=”Circular” option2=”Egg shaped” option3=”Rectangular” option4=”Horse shoe shaped” correct=”option1″]
The correct answer is A. Circular.
A circular cross-section is the most efficient shape for carrying combined flow because it has the least surface area for a given volume. This means that there is less friction between the water and the sewer pipe, which results in less energy loss and a lower head loss.
A circular cross-section is also the strongest shape for a given amount of material. This means that circular sewers are less likely to collapse under the weight of the soil and the water they carry.
Egg-shaped, rectangular, and horse shoe-shaped cross-sections are all less efficient than circular cross-sections. They have more surface area for a given volume, which results in more friction and a higher head loss. They are also weaker than circular cross-sections, which makes them more likely to collapse.
In addition, egg-shaped, rectangular, and horse shoe-shaped cross-sections are more difficult to clean than circular cross-sections. This is because the corners of these shapes create areas where debris can collect. This debris can reduce the flow of water through the sewer and can also create a breeding ground for bacteria.
For all of these reasons, circular cross-sections are the most suitable for carrying combined flow.