281. The height of water level in a tank above the centre of a circular hole 2.5 cm in diameter is 50 m. The velocity of water flowing through the hole, is

A. 31.1 m/sec

B. 31.2 m/sec

C. 31.3 in/sec

D. 31.4 in/sec.

282. Hydraulic coefficient of an orifice means the coefficient of

A. velocity

B. contraction

C. resistance

D. all the above.

283. If Cv, Cc, Cd and Cr are the hydraulic coefficients of an orifice, then

A. Cd = C v. Ce

B. C = 1 + Co21Cd

C. Ce = Ce + Cd

D. C e = C eICd.

284. If vi and uz are the velocities of flow before and after sudden enlargement in a pipe, the head loss given by Carnot and Borda equation, is

A.(022 v12)126,

B. (a ? a2)2/2g

C. (02 ? v)2/2g

D. (01 + c2)212g.

285. Apipe of 0.1 m2 cross sectional area suddenly enlarges to 0.3 in4 cross-sectional area. If the discharge of the pipe is 0.3 m3/sec, the head loss is

A. 2g m of water

B. g/2 m of water

C. lg m of water

D. m of water.

286. In a short cylindercial external mouthpiece, the venacontracta occurs at a distance from the outlet of orifice equal to

A. diameter of the orifice

B. one-fourth the diameter of the orifice

C. one-third the diameter of the orifice

D. two-third the diameter of the orifice

287. The shape of fire hose nozzle is generally kept

A. divergent

B. convergent

C. convergent divergent

D. cylindrical.

Page **41** of **61**