Questions and answers for exam Preparation

MCQs

Total Questions : 2525 | Page 251 of 253 pages

Question 2501. A backward feed multiple effect evaporator is better than forward feed for concentrating cold feed, because it provides __________________?

Higher economy
Lower capacity
Both A. & B.
Lower economy

Discuss Question

Answer: Option A. -> Higher economy
NO EXPLANATION IS AVAILABLE FOR THIS QUESTION!

Question 2502. Pick out the wrong statement?

The capacity of an evaporator is reduced by the boiling point elevation
Corrosive liquid is normally passed through the tubes in a shell and tube heat exchanger
Steam jet ejector is used for vapor compression in a thermal recompression evaporator
Heat sensitive materials should be concentrated in high pressure evaporators

Discuss Question

Answer: Option D. -> Heat sensitive materials should be concentrated in high pressure evaporators
NO EXPLANATION IS AVAILABLE FOR THIS QUESTION!

Question 2503. Pick out the wrong statement ?

In case of heat transfer by purely forced convection, GR/Re 2 ≤ 1
The equivalent diameter of heat transfer for a duct of square cross-section (having each side as ‘x’) is equal to 4x
Distillation process is not the same as evaporation
The effectiveness of nucleate boiling depends basically on the ease with which the bubbles are formed and detached from the heating surface

Discuss Question

Answer: Option B. -> The equivalent diameter of heat transfer for a duct of square cross-section (having each side as ‘x’) is equal to 4x
NO EXPLANATION IS AVAILABLE FOR THIS QUESTION!

Question 2504. Pick out the wrong statement ?

Superheated steam is preferably not used for process heating because of its low heat transfer film co-efficient
In a shell and tube heat exchanger, the shell pressure drop is maximum for orifice baffles
S.I. unit of fouling factor is Watt/m2.°K
Longitudinal fins are used in extended surface heat exchangers, when the direction of fluid flow is parallel to the axis of the tube

Discuss Question

Answer: Option C. -> S.I. unit of fouling factor is Watt/m2.°K
NO EXPLANATION IS AVAILABLE FOR THIS QUESTION!

Question 2505. Pick out the wrong statement?

Orifice baffles are never used in a shell and tube heat exchanger
Pressure drop on the shell side of a heat exchanger depends upon tube pitch also
In a horizontal tube evaporator, surface blanketing by air is avoided
Split ring type and pull through type floating heads are two commonly used floating heads is heat exchangers

Discuss Question

Answer: Option A. -> Orifice baffles are never used in a shell and tube heat exchanger
NO EXPLANATION IS AVAILABLE FOR THIS QUESTION!

Question 2506. Pick out the wrong statement?

Reciprocal of the resistance to heat flow is called thermal conductance
Unit of thermal conductance is W/°K
Thermal conductance of a wall of thickness ‘L’, thermal conductivity ‘k’ and heat flow area ‘A’ is kL/A
None of these

Discuss Question

Answer: Option C. -> Thermal conductance of a wall of thickness ‘L’, thermal conductivity ‘k’ and heat flow area ‘A’ is kL/A
NO EXPLANATION IS AVAILABLE FOR THIS QUESTION!

Question 2507. Which of the following is correct ?

Rate = Driving force × Resistance
Driving force = Rate × Resistance
Resistance = Driving force × Rate
Rate = Resistance/Driving force

Discuss Question

Answer: Option B. -> Driving force = Rate × Resistance
NO EXPLANATION IS AVAILABLE FOR THIS QUESTION!

Question 2508. Pick out the wrong statement ?

The controlling resistance in case of heating of air by condensing steam is in the air fil
The log mean temperature difference (LMTD) for counter flow and parallel flow can be theoretically same when any one of the fluids (hot or cold fluid)
In case of a 1 – 2 shell and tube heat exchanger, the LMTD correction factor value increases sharply, when a temperature cross occurs
Phase change in case of a pure fluid at a given pressure from liquid to vapor or vice-versa occurs at saturation temperature

Discuss Question

Answer: Option C. -> In case of a 1 – 2 shell and tube heat exchanger, the LMTD correction factor value increases sharply, when a temperature cross occurs
NO EXPLANATION IS AVAILABLE FOR THIS QUESTION!

Question 2509. Pick out the wrong statement?

Swenson-Walker crystalliser is a batch crystalliser
Super saturation of the solution is the driving potential for a crystal growth
The liquor left after the removal of crystals from a solution is called mother liquor
The first stage of crystal formation is called nucleation

Discuss Question

Answer: Option A. -> Swenson-Walker crystalliser is a batch crystalliser
NO EXPLANATION IS AVAILABLE FOR THIS QUESTION!

Question 2510. Pick out the wrong statement ?

Heat transfer by radiation cannot occur across an absolute volume
In case of a shell and tube heat exchanger, the pressure drop through the shell is proportional to the number of times the fluid crosses the bundle be
Propagation velocity for travel of heat radiation through vacuum is equal to the velocity of the light
The amount of heat involved in the condensation or vaporisation of 1 kg of a fluid is the same

Discuss Question

Answer: Option A. -> Heat transfer by radiation cannot occur across an absolute volume
NO EXPLANATION IS AVAILABLE FOR THIS QUESTION!