Practice Pakistan's most useful MCQs for competitive exams

In a fully turbulent flow (Re > 105) in a pipe of diameter ‘d’, for a constant pressure gradient, the dependence of volumetric flow rate of an incompressible fluid is_______________?

• (A)  d
• (B)  d2
• (C)  d2.5
• (D)  d4

Answer

Submitted By :Ali Uppal

______________ pumps are axial flow pumps?

• (A)  Turbine
• (B)  Propeller
• (C)  Diffuser
• (D)  None of these

Answer

Submitted By :Ali Uppal

Which of the following equations as suggested by Colebrook and White gives the increase in roughness of a new surface (ε0) with age/time (t) (where, ε = roughness of the surface after time’t’. α = a co-efficient to be experimentally determined) ?

• (A)  ε = ε0 + α.t
• (B)  ε = ε0 + α.t2
• (C)  ε = ε0 + α.t3
• (D)  ε = ε0 + α.t4

Answer

Submitted By :Ali Uppal

The ratio of the depth of flow to the hydraulic radius for the most economical trapezoidal section, in open channel flow is_____________________?

• (A)  0.5
• (B)  1
• (C)  1.5
• (D)  2

Answer

Submitted By :Ali Uppal

Reynolds number for water flow through a tube of I.D. 5 cm is 1500. If a liquid of 5 centipoise viscosity and 0.8 specific gravity flows in the same pipe at the same velocity, then the pressure drop will______________________?

• (A)  Increase
• (B)  Decrease
• (C)  Remain same
• (D)  Data insufficient to predict pressure drop

Answer

Submitted By :Ali Uppal

Which of the following denotes the effect of compressibility in fluid flow ?

• (A)  Weber number
• (B)  Mach number
• (C)  Euler number
• (D)  Reynolds number

Answer

Submitted By :Ali Uppal

A 0.5 m high bed made up of a 1 mm dia glass sphere (density 2500 kg/m3 ) is to be fluidised by water (density 1000 kg/m3 ). If at the point of incipient fluidisation, the bed voidage is 40%, the pressure drop across the bed is________________?

• (A)  4.4 KPa
• (B)  2.94 KPa
• (C)  3.7 KPa
• (D)  None of these

Answer

Submitted By :Ali Uppal

Hydraulic mean depth (Dm) for a circular pipe of diameter ‘D’ flowing full is 0.25 D. For a circular channel, at Dm = 0.3 D, gives the condition for the maximum ?

• (A)  Flow rate
• (B)  Mean velocity
• (C)  Both ‘a’ & ‘b’
• (D)  Neither ‘a’ nor ‘b’

Answer

Submitted By :Ali Uppal

The fluid in which the shearing stress within it is proportional to the velocity gradient across the sheared section, is called a _____________ fluid?

• (A)  Bingham
• (B)  Newtonian
• (C)  Perfect
• (D)  None of these

Answer

Submitted By :Ali Uppal

Nominal size of a pipe is an indication of its ______________ diameter?

• (A)  Inner
• (B)  Outer
• (C)  Approximate
• (D)  None of these

Answer

Submitted By :Ali Uppal