MCQOPTIONS
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MCQOPTIONS
This section includes 40 Mcqs, each offering curated multiple-choice questions to sharpen your Chemical Engineering knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
The minimum shell thickness for tank ≤ 15 metres diameter is limited to __________ mm, for reasons of elastic stability. |
| A. | 5 |
| B. | 2 |
| C. | 15 |
| D. | 10 |
| Answer» D. 10 | |
| 2. |
Minimum recommended baffle spacing in a shell and tube heat exchanger is about (where, D = shell diameter ) |
| A. | 0.5 D |
| B. | 0.2 D |
| C. | 0.80 D |
| D. | 0.66 D |
| Answer» C. 0.80 D | |
| 3. |
In a multiple effect evaporator system having \'n\' effects, the amount of water evaporated per unit surface area in approximately equal to __________ times that in a single effect. |
| A. | (1/n)th |
| B. | 'n'th |
| C. | 1.5 nth |
| D. | 0.5 nth |
| Answer» B. 'n'th | |
| 4. |
Value of Peclet number = ∞, is the representative of |
| A. | complete back mixing, |
| B. | laminar flow. |
| C. | eddy diffusivity = 0. |
| D. | plug flow. |
| Answer» E. | |
| 5. |
The design stress, which is more than the damaging stress, is the least unit stress that will render a member unfit for service before the end of its normal life. The design stress factor or factor of safety indicates the margin between design stress |
| A. | damaging |
| B. | working |
| C. | none of these |
| D. | allowable |
| Answer» B. working | |
| 6. |
for a Tee (used as elbow, entering run) would be around |
| A. | 5 |
| B. | 60 |
| C. | 200 |
| D. | 350 |
| Answer» C. 200 | |
| 7. |
What is the value of ' q ' for saturated vapor feed to a distillation column ?(where q = fraction of the feed stream that is liquid.) |
| A. | 0 |
| B. | 1 |
| C. | <0 |
| D. | > 1 |
| Answer» B. 1 | |
| 8. |
for 90° elbow (medium radius) and 90°square elbow would be respectively around |
| A. | 25 and 60 |
| B. | 3 and 5 |
| C. | 100 and 250 |
| D. | 250 and 600 |
| Answer» B. 3 and 5 | |
| 9. |
Elastic failure of a material occurs, when the tensile stress equals yield strength, yield point or the elastic limit. Also, the elastic failure occurs according to maximum strain theory, when the maximum tensile strain equals (where, ? = yield strength and E = modulus of elasticity) |
| A. | E |
| B. | ? |
| C. | ?/ E |
| D. | E /? |
| Answer» D. E /? | |
| 10. |
The safe height ( h ) to diameter ( d ) ratio (i.e., h / d ) for liquid/petro fuel storage tank of capacity more than 45 kilolitres is less than |
| A. | 1 |
| B. | 2 |
| C. | 3 |
| D. | 3.5 |
| Answer» B. 2 | |
| 11. |
The equivalent diameter for fluid flow through a channel of constant non-circular cross section of area ' A ' is given by (where, P = perimeter of the channel in contact with the fluid) |
| A. | 4 A / P |
| B. | A / P |
| C. | 4 P / A |
| D. | A |
| Answer» B. A / P | |
| 12. |
Diameter of rivet hole ( d , mm) and the plate thickness ( t , mm) are related by Unwin's formula as |
| A. | d = 1.1 t |
| B. | d = 1.6 t |
| C. | d = 1.5 t |
| D. | 3 t |
| Answer» C. d = 1.5 t | |
| 13. |
Equivalent diameter for heat transfer calculation for a duct of square cross-section having each side as ' d ' will be |
| A. | d |
| B. | d |
| C. | 2? d |
| D. | 2 d |
| Answer» D. 2 d | |
| 14. |
In case of a shell and tube heat exchanger, the effect of L / D on inside film heat transfer co-efficient ( h i ) vanishes after a Reynold number of |
| A. | 1000 |
| B. | 3000 |
| C. | 5000 |
| D. | 10000 |
| Answer» E. | |
| 15. |
Joint efficiency ( J ) for a seamless pipe is |
| A. | 1 |
| B. | 0.85 |
| C. | 1.2 |
| D. | < 0.5 |
| Answer» B. 0.85 | |
| 16. |
Stress-strain diagram for low carbon steel/mild steel is shown below in the Fig. The point ' A ' on the Fig. represents the |
| A. | breaking stress |
| B. | ultimate stress |
| C. | elastic limit |
| D. | yield point |
| Answer» D. yield point | |
| 17. |
The raio, is normally taken as |
| A. | 0.15-030 |
| B. | 0.5-0.65 |
| C. | 0.75-0.85 |
| D. | 0.60-0.90 |
| Answer» B. 0.5-0.65 | |
| 18. |
The LMTD correction factor ( F T ) is defined as the |
| A. | ratio of true temperature difference to the LMTD . |
| B. | ratio of LMTD to the true temperature difference. |
| C. | differenced of true temperature difference and the LMTD . |
| D. | geometric mean of the true temperature difference and the LMTD . |
| Answer» B. ratio of LMTD to the true temperature difference. | |
| 19. |
Heat transfer co-efficient, h G (K cal /hr.m 2 .°C) and mass velocity of air, G (kg/hr.m 2 ) for air flow parallel to the surface in case of constant drying rate in batch drying is related as h G = 0.0176 G 0.8 . But when the flow of air perpendicular to the surface is encountered, this equation changes to |
| A. | h G = 1.004 G 0.37 |
| B. | 1.004 G 0.8 |
| C. | hG = 0.0176 G 0.37 |
| D. | 0.0176 G 1.37 |
| Answer» B. 1.004 G 0.8 | |
| 20. |
With increase in temperature drop (in a shell and tube heat exchanger), the LMTD correction factor, F T |
| A. | decreases very rapidly |
| B. | increases very rapidly |
| C. | remains constant |
| D. | increases linearly |
| Answer» B. increases very rapidly | |
| 21. |
The absorption factor is defined as (where, S 1 = slope of the equilibrium curve, S 2 = slope of the operating line) |
| A. | S 1 / S 2 |
| B. | S 1 . S 2 |
| C. | S 2 / S 1 |
| D. | 1/ S 1 . S 2 |
| Answer» B. S 1 . S 2 | |
| 22. |
Pressure drop due to pipe fittings can be estimated by the equation, , where, L e = equivalent length of straight pipeline which will incur the same frictional loss as the fitting and D = diameter of the fitting. The value of (dimensionless) for 45° elbow and 180° close return bends would be respectively around |
| A. | 5 and 10 |
| B. | 45 and 75 |
| C. | 180 and 300 |
| D. | 300 and 500 |
| Answer» C. 180 and 300 | |
| 23. |
In the agitators, the power required will be changed with the increase of diameter of agitator ( D ) as |
| A. | D 2 |
| B. | D 5 |
| C. | D |
| D. | D 9 |
| Answer» C. D | |
| 24. |
In common bubble cap distillation column design practice, riser area is approximately equal to (where, A a = Annular passage area, and S a = Slot area) |
| A. | A a = S a |
| B. | 1.2 A a = 1.2 S a |
| C. | S a = 1.5 A a |
| D. | A a = 1.5 S a |
| Answer» B. 1.2 A a = 1.2 S a | |
| 25. |
Low pressure steam (with saturation temperature between 105 to 120°C) is usually used in the vacuum evaporators, which normally employ a vacuum of about __________ mm Hg (referred to a 760 mm mercury barometer). |
| A. | 250 |
| B. | 450 |
| C. | 650 |
| D. | 750 |
| Answer» D. 750 | |
| 26. |
A perforated plate has holes of diameter d n arranged in a pitch p h . Each hole has a tube of I.D. d t passing through it. The ligament efficiency is given by |
| A. | ( p h - d h )/ p h |
| B. | ( p h - d h . d t /2)/ p h |
| C. | ( p h - d t )/ p h |
| D. | ( p h - d h )/ d h |
| Answer» D. ( p h - d h )/ d h | |
| 27. |
for a Tee (used as elbow, entering branch) would be |
| A. | less than that for Tee (used as elbow, entering run). |
| B. | more than that for Tee (used as elbow, entering run). |
| C. | around 90. |
| D. | both (b) and (c). |
| Answer» E. | |
| 28. |
In a multiple effect evaporator system having ' n ' effects, the amount of water evaporated per unit surface area in approximately equal to __________ times that in a single effect. |
| A. | 'n'th |
| B. | (1/n)th |
| C. | 0.5 nth |
| D. | 1.5 nth |
| Answer» C. 0.5 nth | |
| 29. |
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 5 D . |
| B. | D /5 or minimum 2" to 5 D . |
| C. | D /5 or minimum 2" to D . |
| D. | none of these. |
| Answer» C. D /5 or minimum 2" to D . | |
| 30. |
In the design of a paddle agitator, the ratio is normally taken as |
| A. | 0.1 |
| B. | 0.8 |
| C. | 0.25 |
| D. | 0.5 |
| Answer» C. 0.25 | |
| 31. |
The LMTD correction factor ( F T ) is applied in __________ heat exchangers. |
| A. | 1-1 cocurrent |
| B. | double pipe |
| C. | all multipass |
| D. | all (involving liquid/liquid heat transfer) |
| Answer» D. all (involving liquid/liquid heat transfer) | |
| 32. |
In a shell and tube heat exchanger, the overall heat transfer co-efficient is proportional to the tube side (volumetric flow rate) 0.8 . This is valid, only when the ratio of the tube side film resistance to the total resistance is almost equal to |
| A. | ? |
| B. | 1 |
| C. | 20.8 |
| D. | 2 |
| Answer» C. 20.8 | |
| 33. |
for fully open gate valves would be |
| A. | much more than that for fully open globe valves. |
| B. | much less (say 2% than that for fully open globe valves). |
| C. | around 7. |
| D. | both (b) and (c). |
| Answer» E. | |
| 34. |
Pick out the wrong statement. In an agitated vertical cylinderical reaction vessel, the |
| A. | ratio of liquid depth to tank diameter (i.e. the filling ratio) recommended for most purposes is 1. |
| B. | filling ratio for dispersing gas in a liquid is 2 for sufficiently long contact period. |
| C. | flat bottom and conical bottom vessels have low agitation efficiency for agitation of heavy solids in liquids. |
| D. | dished bottom vessel has very high power consumption. |
| Answer» E. | |
| 35. |
For laminar flow ( N Re < 2100) in steel pipe, the optimum inside pipe diameter is given by |
| A. | D i, opt = 3 Q 0.36 ? 0.18 |
| B. | D i, opt = 3.9 Q 0.45 . ? 0.23 |
| C. | D i, opt = 7.6 Q 0.36 . ? 0.9 |
| D. | D i, opt = 3 Q 0.36 . ? 1.86 ? 0.08 |
| Answer» B. D i, opt = 3.9 Q 0.45 . ? 0.23 | |
| 36. |
What is the value of ' q ' for saturated liquid feed to a distillation column ? |
| A. | 0 |
| B. | <1 |
| C. | 1 |
| D. | >1 |
| Answer» D. >1 | |
| 37. |
Steam side heat transfer co-efficient for design consideration under ordinary condition can be assumed to be about __________ kcal/hr.m 2 .°C. |
| A. | 1250 |
| B. | 2500 |
| C. | 7500 |
| D. | 15000 |
| Answer» D. 15000 | |
| 38. |
It is not desirable to design a heat exchanger for LMTD correction factor, F T , of less than |
| A. | 0.99 |
| B. | 0.95 |
| C. | 0.80 |
| D. | 0.55 |
| Answer» D. 0.55 | |
| 39. |
With increase in the number of shell passes, the value of F T |
| A. | increases |
| B. | decreases |
| C. | remains same |
| D. | remains same, only if the number of tube passes does not change. |
| Answer» B. decreases | |
| 40. |
for fully open globe value may be around |
| A. | 10 |
| B. | 25 |
| C. | 75 |
| D. | 300 |
| Answer» E. | |