Practice Pakistan's most useful MCQs for competitive exams

The thickness of heat transfer plates used in the plate type heat exchanger ranges from _____________ mm, pressed in a single piece provided with grooves & corrugations?

• (A)  0.3 to 0.8
• (B)  1.25 to 3.125
• (C)  3.5 to 7.0
• (D)  8 to12

Answer

Submitted By :Ali Uppal

The ratio of down take area to cross-sectional area of the tube, for calandria type evaporator ranges from_________________?

• (A)  0.5 to 1
• (B)  1 to 1.5
• (C)  1.5 to 2
• (D)  2 to 2.5

Answer

Submitted By :Ali Uppal

A cylindrical pressure vessel of volume 6 πm3 has to be designed to withstand a maximum internal pressure of 10 atm. The allowable design stress of the material is 125N/mm2 and corrosion allowance is 2 mm. The thickness of the vessel for a length/diameter ratio of 3 will be close to________________?

• (A)  5 mm
• (B)  6 mm
• (C)  8 mm
• (D)  10 mm

Answer

Submitted By :Ali Uppal

A single pass air heater is connected to a two pass unit. For the air flow rate and other conditions remaining the same, the film heat transfer co-efficient for air will vary in the ratio of_________________?

• (A)  2
• (B)  20.8
• (C)  20.2
• (D)  None of these

Answer

Submitted By :Ali Uppal

Which of the following factors affect the pressure drop in a co-current gas-liquid absorption packed tower ?

• (A)  Size, shape, orientation and surface of the packing particles
• (B)  Density and viscosity of fluids
• (C)  Fluid flow rates
• (D)  All

Answer

Submitted By :Ali Uppal

The testing pressure of storage tanks and pressure vessels designed as per Indian standard codes should be about ______________ times the design pressure?

• (A)  1.5 to 2
• (B)  3 to 4
• (C)  4 to 5
• (D)  > 5

Answer

Submitted By :Ali Uppal

____________ head is the most economical for cylindrical vessels designed for operating at high pressure (> 15 atm.)?

• (A)  Hemispherical
• (B)  Dished
• (C)  Ellipsoidal
• (D)  Conical

Answer

Submitted By :Ali Uppal

The slope of the feed line in distillation operation is given by (where, q = fraction of the feed stream that is liquid ?

• (A)  -q
• (B)  -q/(1-q)
• (C)  -q/(q-1)
• (D)  None of these

Answer

Submitted By :Ali Uppal

The ratio of tube length to shell diameter in case of liquid shell and tube heat exchanger ranges from__________________?

• (A)  2 to 3
• (B)  3 to 5
• (C)  4 to 8
• (D)  6 to 12

Answer

Submitted By :Ali Uppal

Liquid gradient over the tray results due to the___________________?

• (A)  Resistance offered to flow of liquids by caps & risers and the flow of gas
• (B)  Low gas velocity
• (C)  Large plate spacing
• (D)  Large reflux ratio

Answer

Submitted By :Ali Uppal