162. Hydraulic radius is equal to
A. area divided by the square of wetted perimeter
B. area divided by wetted perimeter
C. wetted perimeter divided by area
D. square root of the area.

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163.  The magnitude of water hammer in a pipe depends upon
A. speed at which value is closed
B. length of the pipe line
C. elastic properties of the pipe material
D. all the above.

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164. In pipe lines, a surge tank is provided
A. to relieve the pressure due to water hammer
B. to provide additional water head
C. to overflow the pipe line when suddenly closed
D. to remove the frictional loss in pipe.

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165. The flow in a channel is said to be non-uniform, if
A. free water surface of an open channel is not parallel to the bed of channel
B. head needed to overcome frictional reistance is less than the drop in elevation of channel bed
C. head needed to overcome fr-..;1_iJ resistance is more than the drop in elevation of channel bed
D. all the above.

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166. Chezy's constant C ? 157.6 is suggested by
A. Bazin
B. Kutter
C. Manning
D. Powell.

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167.  For most economical rectangular section of a channel, the depth is kept
A. one-fourth of the width
B. three times the hydraulic radius
C. half the width
D. hydraulic mean depth

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168.  For the most economical trapezoidal section of a channel with regards to discharge, the required condition, is
A. half of top width = sloping side
B. hydraulic depth = half the depth
C. perpendiculars drawn from the centre of the top width on to the bottom sloping side, are all equal
D. all the above.

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