[amp_mcq option1=”10 cm” option2=”12 cm” option3=”15 cm” option4=”18 cm” correct=”option3″]
The correct answer is C. 15 cm.
The formula for calculating the diameter of a sewer main is:
$d = \sqrt{\frac{4Q}{v}}$
where:
- $d$ is the diameter of the sewer main in meters
- $Q$ is the peak discharge in cubic meters per second
- $v$ is the velocity of the flow in meters per second
Substituting the given values into the formula, we get:
$d = \sqrt{\frac{4(0.0157)}{0.9}} = 15$ cm
The other options are incorrect because they do not result in a diameter that is large enough to accommodate the given peak discharge.