MCQOPTIONS
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MCQOPTIONS
This section includes 482 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 Graetz number is concerned with the |
| A. | Mass transfer between a gas and a liquid |
| B. | Absorption with chemical reaction |
| C. | Heat transfer in turbulent flow |
| D. | Heat transfer in laminar flow |
| Answer» E. | |
| 2. |
Low thermal conductivity of heat insulating materials is due to its%! |
| A. | Dense structure |
| B. | High proportion of air space |
| C. | High specific heat |
| D. | None of these |
| Answer» C. High specific heat | |
| 3. |
A process stream of dilute aqueous solution flowing at the rate of10 Kg.s⁻¹ is to be heated. Steam condensate at 95°C is available for heating purpose, also at a rate of 10 Kg.s⁻¹. A 1 - 1 shell and tube heat exchanger is available. The best arrangement is%! |
| A. | Counter flow with process stream on shell side |
| B. | Counter flow with process stream on tube side |
| C. | Parallel flow with process stream on shell side |
| D. | Parallel flow with process stream on tube side |
| Answer» B. Counter flow with process stream on tube side | |
| 4. |
1 BTU/hr.ft.°F is equal to __________ kcal/hr. m.°C.%! |
| A. | 1.49 |
| B. | 1 |
| C. | 4.88 |
| D. | None of these |
| Answer» B. 1 | |
| 5. |
Value of Prandtl number for water ranges from%! |
| A. | L to 2 |
| B. | 5 to 10 |
| C. | 100 to 500 |
| D. | 1000 to 2000 |
| Answer» C. 100 to 500 | |
| 6. |
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» B. Log mean temperature difference | |
| 7. |
Heat exchangers operating, when the asymptotic range is reached,%! |
| A. | Provide very large heat transfer co-efficient |
| B. | Results in making part of the heating surface inactive |
| C. | Results in abruptly increased velocity |
| D. | None of these |
| Answer» C. Results in abruptly increased velocity | |
| 8. |
Which is the best tube arrangement (in a shell and tube heat exchanger) if the fluids are clean and non-fouling?%! |
| A. | Square pitch |
| B. | Triangular pitch |
| C. | Diagonal square pitch |
| D. | None of these |
| Answer» C. Diagonal square pitch | |
| 9. |
The most conducive surface for dropwise condensation to occur is the __________ surface.%! |
| A. | Coated |
| B. | Oily |
| C. | Glazed & polished |
| D. | Smooth |
| Answer» C. Glazed & polished | |
| 10. |
Absorptivity and refletivity of a perfect black body are respectively%! |
| A. | 1 and 0 |
| B. | 0 and 1 |
| C. | 1 and ? |
| D. | 0 and 0.5 |
| Answer» B. 0 and 1 | |
| 11. |
Fouling factor for a heat exchanger is given by (where, U‚ÇÅ = heat transfer co-efficient of dirty surface U‚ÇÇ = heat transfer co-efficient of clean surface)%! |
| A. | U‚ÇÅ - U‚ÇÇ |
| B. | 1/U‚ÇÅ - 1/U‚ÇÇ |
| C. | 1/U‚ÇÇ - 1/U‚ÇÅ |
| D. | U‚ÇÇ - U‚ÇÅ |
| Answer» C. 1/U‚Äö√á√á - 1/U‚Äö√á√Ö | |
| 12. |
Agitated film evaporator is suitable for concentrating __________ liquids.%! |
| A. | Foaming |
| B. | Viscous |
| C. | Very thin |
| D. | Corrosive |
| Answer» C. Very thin | |
| 13. |
Baffle spacing%! |
| A. | Is not the same as baffle pitch |
| B. | Should be less than one fifth the diameter of the shell |
| C. | Should be less than the inside diameter of the shell |
| D. | None of these |
| Answer» D. None of these | |
| 14. |
Stefan-Boltzman law applies to __________ body.%! |
| A. | Black |
| B. | White |
| C. | Grey |
| D. | Any colour |
| Answer» B. White | |
| 15. |
Unsteady state heat conduction occurs, when%! |
| A. | Temperature distribution is independent of time |
| B. | Temperature distribution is dependent on time |
| C. | Heat flows in one direction only |
| D. | Three dimensional heat flow is concerned |
| Answer» C. Heat flows in one direction only | |
| 16. |
Prandtl and Reynolds analogy are same, when Prandtl number is%! |
| A. | 0.5 |
| B. | 1 |
| C. | > 2 |
| D. | 1.5 |
| Answer» C. > 2 | |
| 17. |
What is the geometric mean of two heat transfer areas A‚ÇÅ and A‚ÇÇ ?%! |
| A. | ‚à ö(A‚ÇÅ . A‚ÇÇ) |
| B. | ‚à ö(A‚ÇÅ + A‚ÇÇ) |
| C. | 1/2 ‚à ö(A‚ÇÅ . A‚ÇÇ) |
| D. | 2 ‚à ö(A‚ÇÅ . A‚ÇÇ) |
| Answer» B. ‚Äö√ √∂(A‚Äö√á√Ö + A‚Äö√á√á) | |
| 18. |
The ratio of velocity head to tube side return loss in case of a multipass shell and tube heat exchanger is%! |
| A. | 2 |
| B. | 1/2 |
| C. | 4 |
| D. | 1/4 |
| Answer» E. | |
| 19. |
The thermal radiative flux from a surface of emissivity = 0.4 is 22.68 kW/m². The approximate surface temperature (K) is (Stefan-Boltzman constant = 5.67xl0⁻⁸ W/m².K⁴)%! |
| A. | 1000 |
| B. | 727 |
| C. | 800 |
| D. | 1200 |
| Answer» B. 727 | |
| 20. |
The average heat transfer co-efficient for laminar film condensation on vertical surface is inversely proportional to (where, ΔT = Temperature drop across condensate film )%! |
| A. | (ΔT)2 |
| B. | ‚à öŒîT |
| C. | (ΔT)1/4 |
| D. | (ΔT)3/2 |
| Answer» D. (≈í√ÆT)3/2 | |
| 21. |
If h‚ÇÅ = inner film co-efficient and /h‚ÇÇ = outer film co-efficient, then the overall heat transfer co-efficient is%! |
| A. | Always less than h‚ÇÅ |
| B. | Always between h‚ÇÅ and h‚ÇÇ |
| C. | Always higher than h‚ÇÇ |
| D. | Dependent on metal resistance |
| Answer» C. Always higher than h‚Äö√á√á | |
| 22. |
Which is the most suitable for the con-certration of highly concentrated solution?%! |
| A. | Open pan evaporation |
| B. | Long tube vertical evaporator |
| C. | Agitated film evaporator |
| D. | None of these |
| Answer» B. Long tube vertical evaporator | |
| 23. |
The film co-efficient between condensing vapour and metal wall increases with%! |
| A. | Increasing temperature of the vapour |
| B. | Decreasing temperature of the vapour |
| C. | Increasing viscosity of the film of condensate |
| D. | Increasing temperature drop |
| Answer» B. Decreasing temperature of the vapour | |
| 24. |
Which of the following is concerned with both heat and mass transfer?%! |
| A. | Lewis relationship |
| B. | Nusselt number |
| C. | Kutateladze number |
| D. | Froude number |
| Answer» B. Nusselt number | |
| 25. |
Mode of heat transfer involved in the cooling of air cooled internal combustion engine is%! |
| A. | Conduction |
| B. | Natural convection |
| C. | Forced convection |
| D. | None of these |
| Answer» C. Forced convection | |
| 26. |
In evaporators, lowering the feed temperature%! |
| A. | Increases the heating area required |
| B. | Reduces the economy |
| C. | Both A and B |
| D. | Decreases the heating area required |
| Answer» D. Decreases the heating area required | |
| 27. |
Which of the following is not used as a medium for high temperature heating?%! |
| A. | Dowtherm |
| B. | Mercury |
| C. | Liquid metal (e.g. molten sodium) |
| D. | Fused salts (e.g., an eutectic mixture of 53% KNO‚ÇÉ, 40% NaNO‚ÇÇand 7% NaNO‚ÇÉ) |
| Answer» C. Liquid metal (e.g. molten sodium) | |
| 28. |
Multiple effect evaporation accounts for%! |
| A. | Steam economy |
| B. | Lower operating costs |
| C. | Investment economy |
| D. | None of these |
| Answer» B. Lower operating costs | |
| 29. |
In a cooling tower, water becomes cool by%! |
| A. | Loosing sensible heat |
| B. | Heat transfer to surroundings |
| C. | Vaporisation due to heat loss to air |
| D. | Loosing latent heat |
| Answer» B. Heat transfer to surroundings | |
| 30. |
In SI units, fouling factor is expressed in%! |
| A. | m²°K/W |
| B. | W/m²°K |
| C. | m²°K |
| D. | m°K/W |
| Answer» B. W/m¬¨‚⧬¨‚àûK | |
| 31. |
For a counter current heat exchanger with Tih = 80°C, T°c = 60°C, T°h = 50°C and Tic = 30°C, and the temperature difference between the two streams being the same everywhere along Z, the direction of flow of hot fluid. The temperature profile should satisfy%! |
| A. | d²T/dZ² > 0 |
| B. | d²T/dZ² = 0 |
| C. | d²T/dZ² < 0 |
| D. | dT/dZ = 0 |
| Answer» C. d¬¨‚â§T/dZ¬¨‚⧠< 0 | |
| 32. |
Multiple effect evaporation is generally recommended, when the%! |
| A. | Large scale evaporation of liquor is needed |
| B. | Corrosive liquids are to be concentrated |
| C. | Fuel is cheaply available |
| D. | Evaporation on small scale is to be done |
| Answer» B. Corrosive liquids are to be concentrated | |
| 33. |
For what value of Prandtl number, the Col-burn analogy is valid?%! |
| A. | 0.06 to 120 |
| B. | 0.6 to 120 |
| C. | 1 to 103 |
| D. | L to 50 |
| Answer» C. 1 to 103 | |
| 34. |
The rate of heat transfer from a vertical plate by natural convection depends upon the temperature differences (ΔT) between wall and outside bulk. The proportionality is given as%! |
| A. | (ΔT)1/4 |
| B. | (ΔT)1/2 |
| C. | (ΔT)5/4 |
| D. | (ΔT)3/4 |
| Answer» E. | |
| 35. |
Extremely large or small volumes of fluids are generally best routed through the shell side of a shell and tube heat exchanger, because of the%! |
| A. | Less corrosion problems |
| B. | Flexibility possible in the baffle arrangement |
| C. | Low pressure drop |
| D. | High heat transfer co-efficient |
| Answer» C. Low pressure drop | |
| 36. |
Graetz number is given by%! |
| A. | mCp/kL |
| B. | kL/mCp |
| C. | mCp/kμ |
| D. | kμ/mCp |
| Answer» B. kL/mCp | |
| 37. |
Use of transverse baffles in a shell and tube heat exchanger is done to increase the%! |
| A. | Rate of heat transfer |
| B. | Flow velocity |
| C. | Turbulence of shell side fluid |
| D. | All of the above |
| Answer» E. | |
| 38. |
All analogy equations connecting friction factor and heat transfer co-efficient apply only to%! |
| A. | Wall or skin friction |
| B. | Form friction |
| C. | Both A and B |
| D. | Turbulent flow |
| Answer» B. Form friction | |
| 39. |
Boiling of milk in an open vessel is an example of __________ boiling.%! |
| A. | Film |
| B. | Sub-cooled |
| C. | Saturated nucleate |
| D. | None of these |
| Answer» B. Sub-cooled | |
| 40. |
Heat transfer by __________ may not necessarily require the presence of a medium.%! |
| A. | Conduction |
| B. | Natural convection |
| C. | Forced convection |
| D. | Radiation |
| Answer» E. | |
| 41. |
The variation of thermal conductivity of a metal with temperature is often correlated using an expression of the form K = K₀ + at. where, K is the thermal conductivity and T is the temperature (in °K). The units of 'a' in SI system will be%! |
| A. | W/m.k |
| B. | W/m |
| C. | W/m.k² |
| D. | None, A is just a number |
| Answer» D. None, A is just a number | |
| 42. |
Bulk of the convective heat transfer resistance from a hot tube surface to the fluid flowing in it, is%! |
| A. | In the central core of the fluid |
| B. | Uniformly distributed throughout the fluid |
| C. | Mainly confined to a thin film of fluid near the surface |
| D. | None of these |
| Answer» D. None of these | |
| 43. |
In a single evaporator system, the steam economy __________ by creating vacuum in the evaporator.%! |
| A. | Increases |
| B. | Decreases |
| C. | Remains constant |
| D. | May increase or decrease, depends on the vacuum |
| Answer» B. Decreases | |
| 44. |
Air is to be heated by condensing steam. Two heat exchangers are available (i) a shell and tube heat exchanger and (ii) a finned tube heat exchanger. Tube side heat transfer area are equal in both the cases. The recommended arrangement is%! |
| A. | Finned tube heat exchanger with air inside and steam outside |
| B. | Finned tube heat exchanger with air outside and steam inside |
| C. | Shell and tube heat exchanger with air inside tubes and steam on shell side |
| D. | Shell and tube heat exchanger with air on shell side and steam inside tubes |
| Answer» C. Shell and tube heat exchanger with air inside tubes and steam on shell side | |
| 45. |
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» B. Log mean temperature difference | |
| 46. |
In a forward feed multiple effect, the pressure build up will be%! |
| A. | Least at the inlet of the first effect |
| B. | Least at the outlet of the last effect |
| C. | Highest at the inlet of the last effect |
| D. | Highest at the outlet of the last effect |
| Answer» C. Highest at the inlet of the last effect | |
| 47. |
At what value of Prandtl number, the hydrodynamic and thermal boundary layers of a fluid flowing over a heated plate will be identical?%! |
| A. | 1 |
| B. | < 1 |
| C. | > 1 |
| D. | None of these |
| Answer» B. < 1 | |
| 48. |
Three solid objects of the same material and of equal mass-a sphere, a cylinder (length = diameter) and a cube are at 500°C initially. These are dropped in a quenching bath containing a large volume of cooling oil each attaining the bath temperature eventually. The time required for 90% change in temperature is the smallest for%! |
| A. | Cube |
| B. | Cylinder |
| C. | Sphere |
| D. | Equal for all the three |
| Answer» B. Cylinder | |
| 49. |
For small temperature difference, the heat transfer rate as per Newton's law of cooling is proportional to (where, Δt = excess temperature)%! |
| A. | Δt |
| B. | Δt² |
| C. | Δt³ |
| D. | ‚à öŒît |
| Answer» B. ≈í√Æt¬¨‚⧠| |
| 50. |
Indirect contact heat exchangers are preferred over direct contact heat exchangers, because%! |
| A. | Heat transfer co-efficient are high |
| B. | There is no risk of contamination |
| C. | There is no mist formation |
| D. | Cost of equipment is lower |
| Answer» C. There is no mist formation | |