288. A short tube mouthpiece will not run full at its outlet if the head under which the orifice works, is

A. less than 12.2 m of the water

B. more than 12.2 m of the water

C. equal of 12.2 m of water

D. none of these.

289. A piezometer opening in pipes measures

A. velocity head

B. static pressure

C. total pressure

D. negative static pressure.

290. In an inclined position, a venturimeter records

A. more reading

B. less reading

C. same reading

D. none of these.

291. If H is the difference of liquid levels on two sides of an orifice (width b, depth d), the discharge through the orifice will be

A. Cdbd2V2gH

B. C db2c142gH

C. Cdbc1^12gH

D. C dbd.2g H1'2.

292. Water flows through a convergent mouthpiece of diameter 4 cm at convergence under a head of 3 metres. If the maximum vacuum pressure is 9 metres of water, the maximum diameter of divergence, to aviod separation of flow, is

A. 4 cm

B. 6 cm

C. 4--T cm

D. 2i-8- cm.

293. 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.

294. 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

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