[amp_mcq option1=”Mean radius of sewer” option2=”Difference in heads between two points in circular pipes” option3=”Mean of radii in a pipe line of varying cross-sections” option4=”Cross-sectional area/wetted perimeter” correct=”option4″]
The correct answer is D. Cross-sectional area/wetted perimeter.
The hydraulic mean radius is a dimensionless quantity used in hydraulics to characterize the flow of a fluid in a pipe. It is defined as the ratio of the cross-sectional area of the pipe to the wetted perimeter of the pipe. The wetted perimeter is the length of the pipe that is in contact with the fluid. The hydraulic mean radius is used to calculate the head loss in a pipe, which is the difference in pressure between two points in the pipe.
Option A is incorrect because the mean radius of a sewer is not the same as the hydraulic mean radius. The mean radius is simply the average of the radii of the sewer, while the hydraulic mean radius is a dimensionless quantity that takes into account the cross-sectional area and wetted perimeter of the sewer.
Option B is incorrect because the difference in heads between two points in circular pipes is not the same as the hydraulic mean radius. The difference in heads is the difference in pressure between two points in the pipe, while the hydraulic mean radius is a dimensionless quantity that takes into account the cross-sectional area and wetted perimeter of the pipe.
Option C is incorrect because the mean of radii in a pipe line of varying cross-sections is not the same as the hydraulic mean radius. The mean of radii is simply the average of the radii of the pipe, while the hydraulic mean radius is a dimensionless quantity that takes into account the cross-sectional area and wetted perimeter of the pipe.