MCQOPTIONS
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MCQOPTIONS
This section includes 425 Mcqs, each offering curated multiple-choice questions to sharpen your Chemical Engineering knowledge and support exam preparation. Choose a topic below to get started.
| 401. |
A measure of the extent to which viscous heating is important relative to the heat flow resulting from the impressed temperature difference is represented by the _______________ number? |
| A. | Condensation |
| B. | Grashoff |
| C. | Stanton |
| D. | Brinkman |
| Answer» E. | |
| 402. |
A long iron rod initially at a temperature of 20°C has one end dipped in boiling water (100°C) at time, t = 0. The curved surface of the rod is insulated so that heat conduction is one dimensional in the axial direction. The temperature at a distance 100 mm from the dipped end becomes 40°C at time, t = 200 s. The same temperature is achieved at a distance of 200 mm from the dipped end at time ___________________? |
| A. | t = 283 s |
| B. | t = 356 s |
| C. | t = 400 s |
| D. | t = 800 s |
| Answer» E. | |
| 403. |
A hot liquid is kept in a big room. The logarithm of the numerical value of the temperature difference between the liquid and the room is plotted against time. The plot will be very nearly a/an___________________? |
| A. | Ellipse |
| B. | Straight line |
| C. | Parabola |
| D. | Circular arc |
| Answer» C. Parabola | |
| 404. |
A hot body will radiate heat most rapidly, if its surface is___________________? |
| A. | White & rough |
| B. | Black & rough |
| C. | White & polished |
| D. | Black & polished |
| Answer» C. White & polished | |
| 405. |
A hollow sphere and a solid sphere of the same material and equal radii are heated to the same temperature. In this case ? |
| A. | The cooling rate will be the same for the two spheres and hence the two spheres will have equal temperatures at any instant |
| B. | Both the spheres will emit equal amount of radiation per unit time in the beginning |
| C. | Both will absorb equal amount of radiation from the surrounding in the beginning |
| D. | Both B. & C. |
| Answer» E. | |
| 406. |
A graph between _____________ is called Wilson plot? |
| A. | (1/U) Vs. (1/v0.8) |
| B. | (1/v0.8) Vs. U |
| C. | v0.8 Vs . U |
| D. | (1/U) Vs. (1/V) |
| Answer» B. (1/v0.8) Vs. U | |
| 407. |
A fluid is flowing inside the inner tube of a double pipe heat exchanger with diameter ‘d’. For a fixed mass flow rate, the tube side heat transfer co-efficient for turbulent flow conditions is proportional to_____________________? |
| A. | d0.8 |
| B. | d-0.2 |
| C. | d-1 |
| D. | d-1.8 |
| Answer» C. d-1 | |
| 408. |
A _____________ evaporator employs an annular downtake? |
| A. | Basket type |
| B. | Horizontal |
| C. | Long tube vertical |
| D. | None of these |
| Answer» B. Horizontal | |
| 409. |
A dilute aqueous solution is to be concentrated in an evaporator system. High pressure steam is available. Multiple effect evaporator system is employed, because__________________? |
| A. | Total heat transfer area of all the effects is -less than that in a single effect evaporator system |
| B. | Total amount of vapor produced per Kg of feed steam in a multiple effect system is much higher than in a single effect |
| C. | Boiling point elevation in a single effect system is much higher than that in any effect in a multi-effect system |
| D. | Heat transfer co-efficient in a single effect is much lower than that in any effect in a multieffect system |
| Answer» C. Boiling point elevation in a single effect system is much higher than that in any effect in a multi-effect system | |
| 410. |
A diathermanous substance _______________ the thermal radiation completely? |
| A. | Absorbs |
| B. | Reflects |
| C. | Transmits |
| D. | None of these |
| Answer» D. None of these | |
| 411. |
A dephlegmator is a_____________________? |
| A. | Total condenser |
| B. | Vacuum evaporator |
| C. | Partial condenser |
| D. | Double pipe heat exchanger |
| Answer» D. Double pipe heat exchanger | |
| 412. |
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» D. kA >2 kB | |
| 413. |
A composite flat wall of a furnace is made of two materials ‘A’ and ‘B’. The thermal conductivity of ‘A’ is twice of that of material ‘B’, while the thickness of layer of ‘A’ is half that of B. If the temperature at the two sides of the wall are 400 and 1200°K, then the temperature drop (in °K) across the layer of material ‘A’ is________________? |
| A. | 125 |
| B. | 133 |
| C. | 150 |
| D. | 160 |
| Answer» E. | |
| 414. |
A BTU/hr.ft.2 °F is equal to_________________? |
| A. | 1 kcal/hr. m2°C |
| B. | 4.88 kcal/hr. m.2°C |
| C. | 1 kcal/hr. m2.°K |
| D. | None of these |
| Answer» C. 1 kcal/hr. m2.°K | |
| 415. |
A body is called grey if the monochromatic emissivity of the body is___________________? |
| A. | Zero |
| B. | Unity |
| C. | Same for all wavelengths |
| D. | Different for all wavelengths |
| Answer» D. Different for all wavelengths | |
| 416. |
A body cools down from 75°C to 70°C in 10 minutes. It will cool down from 70° C to 65° C in ______________ minutes? |
| A. | 10 |
| B. | > 10 |
| C. | < 10 |
| D. | Either B. or C., depends on the mass of the body |
| Answer» C. < 10 | |
| 417. |
A black body does not ____________ radiation? |
| A. | Absorb or emit |
| B. | Refract |
| C. | Reflect |
| D. | Both B. & C. |
| Answer» E. | |
| 418. |
A black body when hot, emits heat radiation of _____________ wavelengths? |
| A. | Small |
| B. | Large |
| C. | All |
| D. | One fixed |
| Answer» D. One fixed | |
| 419. |
A backward feed multiple effect evaporator is better than forward feed for concentrating cold feed, because it provides __________________? |
| A. | Higher economy |
| B. | Lower capacity |
| C. | Both A. & B. |
| D. | Lower economy |
| Answer» B. Lower capacity | |
| 420. |
A 2-4 heat exchanger involves__________________? |
| A. | Only counter-flow of fluids |
| B. | Only parallel-flow of fluids |
| C. | Both counter and parallel-flow of the fluids |
| D. | Smaller pressure drop compared to 1-2 exchanger |
| Answer» D. Smaller pressure drop compared to 1-2 exchanger | |
| 421. |
A 10 cm dia steam pipe, carrying steam at 180°C, is covered with an insulation (conductivity = 0.6 W/m.°C). It losses heat to the surroundings at 30°C. Assume a heat transfer co-efficient of 0.8 W/m2.°C for heat transfer from surface to the surroundings. Neglect wall resistance of the pipe and film resistance of steam. If the insulation thickness is 2 cms, the rate of heat loss from this insulated pipe will be__________________? |
| A. | Greater than that for un-insulated steam pipe |
| B. | Less than that of the un-insulated steam pipe |
| C. | Equal to that of the un-insulated steam pipe |
| D. | Less than the steam pipe with 5 cms insulation |
| Answer» C. Equal to that of the un-insulated steam pipe | |
| 422. |
200 kg of solids (on dry basis) is subjected to a drying process for a period of 5000 seconds. The drying occurs in the constant rate period with the drying rate as, Nc = 0.5 × 10-3 kg/m2.s. The initial moisture content of the solid is 0.2 kg moisture/kg dry solid. The interfacial area available for drying is 4 m2/1000 kg of dry solid. The moisture content at the end of the drying period is (in kg moisture/kg dry solid)? |
| A. | 0.5 |
| B. | 0.05 |
| C. | 0.1 |
| D. | 0.15 |
| Answer» D. 0.15 | |
| 423. |
1000 Kg of liquid at 30°C in a well stirred vessel has to be heated to 120°C, using immersed coils carrying condensing steam at 150°C. The area of the steam coils is 1.2 m2 and the overall heat transfer co-efficient to the liquid is 1500 W/m2.°C. Assuming negligible heat loss to the surrounding and specific heat capacity of the liquid to be 4 kJ/kg.°C, the time taken for the liquid to reach desired temperature will be__________________? |
| A. | 15 min |
| B. | 22 min |
| C. | 44 min |
| D. | 51 min |
| Answer» E. | |
| 424. |
1000 kg of wet solids are to be dried from 60% to 20% moisture (by weight). The mass of moisture removed in kg is__________________? |
| A. | 520 |
| B. | 200 |
| C. | 400 |
| D. | 500 |
| Answer» E. | |
| 425. |
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 | |