127. An orifice is called a large orifice if water head, is

A. twice the diameter of the orifice

B. thrice the diameter of the orifice

C. four times the diameter of the orifice

D. five times the diameter of the orifice.

128. Discharge through a totally submerged orifice, is directly proportional to

A. difference in elevation of water surfaces

B. square root of the difference in elevation of water surface

C. square root of the opening

D. reciprocal of the area of the opening

129. The width of a weir with end contraction, is

A. equal to the width of the channel

B. less than the width of the channel

C. half the width of the channel

D. none of these.

130. The upper surface of the weir over which water flows, is known as

A. vein

B. nappe

C. sill

D. none of these.

131. Discharge Q over a rectangular weir of length L and height H, is given by the equation

A. Q = 2/3 CdIT-g LH3/2

B. Q = 2/3 C dL HAI2gH

C. Q = 2/3 C

D. all the above.

132. To ensure that water does not rise more than 100 cm above the crest, for a discharge of 5.00 m3/sec, the length of water will be

A. 2.48 m

B. 2.49 m

C. 2.50 m

D. 2.51 m.

133. If S is the length of the crest, H is the height of water source of a weir whose length is L and discharge is Q m3/sec, the velocity of approach Vd is

A. -^12,gH

B. L(H L)

C. L(H + S)

D. L(H + S)

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