Practice Pakistan's most useful MCQs for competitive exams

Pump used for the transportation of molten sodium in a fast breader reactor is a/an __________ pump?

• (A)  Reciprocating
• (B)  Plunger
• (C)  Electromagnetic
• (D)  Gear

Answer

Submitted By :Ali Uppal

Which is the correct relationship for a centrifugal pump? (Where, D = Impeller diameter, inches H = Head developed, ft of liquid pumped N = Speed of pump, rpm) ?

• (A)  D = 1840 H0.5/N
• (B)  D = 1840 N/H0.5
• (C)  H = 1840 D0.5/N
• (D)  D = 1840 H/N

Answer

Submitted By :Ali Uppal

The terminal velocity of a particle moving through a fluid varies as dp n. The value of n is equal to _______________ in Stoke’s law regime?

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

Answer

Submitted By :Ali Uppal

Maximum theoretical suction lift for water at 15°C by a centrifugal pump is 34 ft. The same for water at 90°C will be _____________________ ft?

• (A)  40
• (B)  34
• (C)  8
• (D)  37

Answer

Submitted By :Ali Uppal

For the same terminal conditions and valve size, the pressure drop in a fully opened globe valve as compared to that in a gate valve is___________________?

• (A)  More
• (B)  Less
• (C)  Equal
• (D)  Either

Answer

Submitted By :Ali Uppal

The drag co-efficient for a bacterium moving in water at 1 mm/s, will be of the following order of magnitude (assume size of the bacterium to be 1 micron and kinematic viscosity of water to be 10-6m2/s) ?

• (A)  24000
• (B)  24
• (C)  0.24
• (D)  0.44

Answer

Submitted By :Ali Uppal

A piezometer opening measures the _____________ fluid pressure?

• (A)  Static
• (B)  Undisturbed
• (C)  Total
• (D)  Dynamic

Answer

Submitted By :Ali Uppal

A particle A of diameter 10 microns settles in an oil of specific gravity 0.9 and viscosity 10 poise under Stoke’s law. A particle B with diameter 20 microns settling in the same oil will have a settling velocity ?

• (A)  Same as that of A
• (B)  One fourth as that of A
• (C)  Twice as that of A
• (D)  Four times as that of A

Answer

Submitted By :Ali Uppal

With increase in the shear rate, the apparent viscosity of pseudo-plastic fluids__________________?

• (A)  Increases
• (B)  Decreases
• (C)  Remain same
• (D)  May increase or decrease; depends on the magnitude of shear rate

Answer

Submitted By :Ali Uppal

If the discharge of a centrifugal pump is throttled, then its suction lift_______________________?

• (A)  Increases
• (B)  Decreases
• (C)  Remains unchanged
• (D)  Data insufficient to predict

Answer

Submitted By :Ali Uppal