Practice Pakistan's most useful MCQs for competitive exams

To reduce the tube side pressure drop for the same flow rate, the heat exchanger recommended is _______________?

• (A)  1-2 heat exchanger
• (B)  1-1 heat exchanger
• (C)  3-2 heat exchanger
• (D)  2-4 heat exchanger

Answer

Submitted By :Ali Uppal

In case of _______________ boiling, the liquid temperature is below the saturation temperature and the boiling takes place in the vicinity of the heated surface?

• (A)  Nucleate
• (B)  Local
• (C)  Pool
• (D)  Saturated

Answer

Submitted By :Ali Uppal

For _______________ Prandtl number values, the heat conduction will be negligible in the buffer zone?

• (A)  Extremely low
• (B)  Low
• (C)  High
• (D)  No

Answer

Submitted By :Ali Uppal

Terminal point temperature differences between fluids in case of a heat exchanger is termed as__________________?

• (A)  Approach
• (B)  Log mean temperature difference
• (C)  Arithmetic mean temperature difference
• (D)  Geometric mean temperature difference

Answer

Submitted By :Ali Uppal

A composite wall consists of two plates A and B placed in series normal to the flow of heat. The thermal conductivities are kA and kB and the specific heat capacities are CPA and CPB for plates A and B respectively. Plate B has twice the thickness of plate A. At steady state, the temperature difference across plate A is greater than that across plate B, when_________________?

• (A)  CPA > CPB
• (B)  CPA < CPB
• (C)  kA < 0.5 kB
• (D)  kA >2 kB

Answer

Submitted By :Ali Uppal

Overall heat transfer co-efficient of a particular tube is U1. If the same tube with some dirt deposited on either side has coefficient U2, then_________________?

• (A)  U1 = U2
• (B)  U2 > U1
• (C)  U1 > U2
• (D)  U1 = dirt factor – U2

Answer

Submitted By :Ali Uppal

Maximum heat transfer rate is achieved in _____________ flow?

• (A)  Co-current
• (B)  Counter-current
• (C)  Turbulent
• (D)  Laminar

Answer

Submitted By :Ali Uppal

Radiator of an automobile engine is a ______________ type of heat exchanger?

• (A)  Co-current
• (B)  Cross-current
• (C)  Counter-current
• (D)  Direct contact

Answer

Submitted By :Ali Uppal

In SI units, thermal conductivity is expressed in__________________?

• (A)  Watt/m.°K
• (B)  Watt/m2. °K
• (C)  Watt/m2. °K
• (D)  Watt/m4. °K

Answer

Submitted By :Ali Uppal

In pipe flow, heat is transferred from hot wall to the liquid by__________________?

• (A)  Conduction only
• (B)  Forced convection only
• (C)  Forced convection and conduction
• (D)  Free and forced convection

Answer

Submitted By :Ali Uppal