Practice Pakistan's most useful MCQs for competitive exams

1.2 to 3.8 cms is the value of the ______________________?

• (A)  Downcomer liquid seal in case of a balanced tray design
• (B)  Static submergence in case of a bubble cap tray for column operating under pressure (≥ 1 atm)
• (C)  Skirt clearance for bubble caps
• (D)  All

Answer

Submitted By :Ali Uppal

The longitudinal stress induced in a thin walled cylindrical vessel under internal pressure is_________________?

• (A)  pd/2t
• (B)  pd/4t
• (C)  pd/t
• (D)  pd/8t

Answer

Submitted By :Ali Uppal

Scale up problem in design based on the similarity concept takes into account _______________ similarity?

• (A)  Geometrical
• (B)  Kinematic
• (C)  Dynamic
• (D)  All

Answer

Submitted By :Ali Uppal

For turbulent flow (NRe > 2100) of low viscosity fluid (μ > 20cp) in steel pipes, the optimum inside pipe diameter is given by(where, Q = fluid flow rate, ft3/sec, ρ = fluid density, lb/ft3 μ = fluid viscosity, centipoise Di = optimum inside pipe diameter, inches) ?

• (A)  Di, opt = 3.9 Q0.45 ρ0.13
• (B)  Di, opt = 3.9 Q0.45. μ0.95
• (C)  Di, opt = 4.7 Q0.36. μ3.2ρ0.13
• (D)  Di, opt = 3 Q0.36. μ0.88

Answer

Submitted By :Ali Uppal

If ‘D’ is the inside diameter of the shell of a shell and tube heat exchanger, then the baffle spacing is usually in the range of__________________?

• (A)  D/2 or minimum 2″ to 5D
• (B)  D/5 or minimum 2″ to 5D
• (C)  D/5 or minimum 2″ to D
• (D)  None of these

Answer

Submitted By :Ali Uppal

In a shell and tube heat exchanger, the shortest centre to centre distance between the adjacent tubes is__________________?

• (A)  Called tube pitch
• (B)  Called tube clearance
• (C)  Always less than the diameter of the tube
• (D)  None of these

Answer

Submitted By :Ali Uppal

In hydrostatic testing of welded pipe (for leakage, strength etc.) the ratio of minimum hydrostatic test pressure to internal design pressure is around __________________?

• (A)  0.5
• (B)  1.5
• (C)  2.5
• (D)  3.5

Answer

Submitted By :Ali Uppal

Tube wall thickness depends on the corrosiveness of the fluids and their operating pressure & temperature and is specified by Birmingham wire gauge (B.W.G)-a number which varies from 8 to 18 with the numbers 14 and 16 being more commonly used. Outside diameter of tubes varies from about 15 to 50 mm; however a tube of less than _____________ mm outside diameter is generally not recommended for fouling fluids ?

• (A)  16
• (B)  19
• (C)  28
• (D)  38

Answer

Submitted By :Ali Uppal

For a 25 mm hole drilled in plates to be riveted, the shank diameter of the rivet should be _______________ mm?

• (A)  25
• (B)  23
• (C)  26
• (D)  27

Answer

Submitted By :Ali Uppal

In case of a ‘thin’ pressure vessel, the ratio of its diameter to wall thickness is_________________?

• (A)  < 10
• (B)  > 10
• (C)  > 20
• (D)  30

Answer

Submitted By :Ali Uppal