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.
| 351. |
The Sieder-Tate correlation for heat transfer in turbulent flow in pipe gives Nu α Re0.8, where, Nu is the Nusselt number and Re is the Reynolds number for the flow. Assuming that this relation is valid, the heat transfer co-efficient varies with the pipe diameter (D) as$? |
| A. | (D)-1.8 |
| B. | (D)-0.2 |
| C. | (D)0.2 |
| D. | (D)1.8 |
| Answer» C. (D)0.2 | |
| 352. |
If a single tube pass heat exchanger is converted to two pass, then for the same flow rate, the pressure drop per unit length in tube side will$? |
| A. | Increase by 1.8 times |
| B. | Decrease by 22 |
| C. | Increase by 216 |
| D. | Remain unchanged |
| Answer» D. Remain unchanged | |
| 353. |
The separation of liquid droplets from the vapor is done by a/an __________ , in the evaporators.$? |
| A. | Steam ejector |
| B. | Entrainment separator |
| C. | Compressor |
| D. | Vacuum pump |
| Answer» C. Compressor | |
| 354. |
Radiator of an automobile engine is a __________ type of heat exchanger.$? |
| A. | Co-current |
| B. | Cross-current |
| C. | Counter-current |
| D. | Direct contact |
| Answer» E. | |
| 355. |
Controlling heat transfer film co-efficient is the one, which offers __________ resistance to heat transfer.$? |
| A. | No |
| B. | The least |
| C. | The largest |
| D. | Lower |
| Answer» D. Lower | |
| 356. |
In case of a vertical tube evaporator, with increase in the liquor level, the __________ is increased.$? |
| A. | Velocity of circulation |
| B. | Liquor-film co-efficient |
| C. | Both A and B |
| D. | Neither A and B |
| Answer» E. | |
| 357. |
For condensation of pure vapors, if the heat transfer co-efficients in filmwise and drop-wise condensation are respectively hf and hd, then$? |
| A. | hf = hd |
| B. | hf > hd |
| C. | hf < hd |
| D. | hf could be greater or smaller than hd |
| Answer» D. hf could be greater or smaller than hd | |
| 358. |
Fqra cold viscous feed, backward feed gives __________ than forward feed.$? |
| A. | A higher capacity |
| B. | A lower capacity |
| C. | Lower economy |
| D. | None of these |
| Answer» B. A lower capacity | |
| 359. |
In a liquid-liquid heat exchanger, for the same process temperature, the ratio of the LMTD in parallel flow to the LMTD in counter flow is always$? |
| A. | < 1 |
| B. | > 1 |
| C. | 1 |
| D. | ‚à û |
| Answer» B. > 1 | |
| 360. |
In SI units, thermal conductivity is expressed in$? |
| A. | Watt/m.°K |
| B. | Watt/m². °K |
| C. | Watt/m². °K |
| D. | Watt/m4. °K |
| Answer» B. Watt/m¬¨‚â§. ¬¨‚àûK | |
| 361. |
Which of the following has maximum thermal conductivity at the same temperature?$? |
| A. | Steel |
| B. | Petrol |
| C. | Air |
| D. | All of the above |
| Answer» B. Petrol | |
| 362. |
Steam economy in case of a triple effect evaporator will be$? |
| A. | 1 |
| B. | < 1 |
| C. | > 1 |
| D. | Between 0 and 1 |
| Answer» D. Between 0 and 1 | |
| 363. |
As the difference between the wall temperature and bulk temperature increases, the boiling heat transfer co-efficient$? |
| A. | Continues to increase |
| B. | Continues to decrease |
| C. | Goes through a minimum |
| D. | Goes through a maximum |
| Answer» D. Goes through a maximum | |
| 364. |
Steady state one dimensional heat flow by conduction as given by Fourier's low does not assume that$? |
| A. | There is no internal heat generation |
| B. | Boundary surfaces are isothermal |
| C. | Material is anisotropic |
| D. | Constant temperature gradient exists |
| Answer» D. Constant temperature gradient exists | |
| 365. |
Overall heat transfer co-efficient for cooling of hydrocarbons by water is about$? |
| A. | 50 -100 Kcal/hr.m².°C |
| B. | 50 -100 W/m² . °K |
| C. | 50 -100 BTU/hr. ft.2°F |
| D. | 1000 - 1500 BTU/hr. ft.2°F |
| Answer» D. 1000 - 1500 BTU/hr. ft.2¬¨‚àûF | |
| 366. |
The inner wall of a furnace is at a temperature of 700°C. The composite wall is made of two substances, 10 and 20 cm thick with thermal conductivities of 0.05 and 0.1 W.m-1.°C-1 respectively. The ambient air is at 30°C and the heat transfer co-efficient between the outer surface of wall and air is 20 W.m⁻².°C-1. The rate of heat loss from the outer surface in W.m-2is$? |
| A. | 165.4 |
| B. | 167.5 |
| C. | 172.5 |
| D. | 175 |
| Answer» B. 167.5 | |
| 367. |
Boiling point elevation for a strong and concentrated solution is found by Duhring's rule, which states that at the same pressure, the boiling point of a solution is a linear function of the __________ of pure water.$? |
| A. | Boiling point |
| B. | Dynamic viscosity |
| C. | Kinematic viscosity |
| D. | Density |
| Answer» B. Dynamic viscosity | |
| 368. |
Double pipe heat exchangers are used$? |
| A. | When heat transfer area required is very high |
| B. | When heat transfer area required is very low, i.e (100-200 ft²) |
| C. | Because it occupies less floor area |
| D. | Because it is less costly |
| Answer» C. Because it occupies less floor area | |
| 369. |
Steam is to be condensed in a shell and tube heat exchanger, 5 m long with a shell diameter of 1 m. Cooling water is to be used for removing the heat. Heat transfer co-efficient for the cooling water, whether on shell side or tube side is the same. The best arrangement is$? |
| A. | Vertical heat exchanger with steam on tube side |
| B. | Vertical heat exchanger with steam on shell side |
| C. | Horizontal heat exchanger with steam on tube side |
| D. | Horizontal heat exchanger with steam on shell side |
| Answer» C. Horizontal heat exchanger with steam on tube side | |
| 370. |
When the ratio of the Grashoff number and to the square of Reynolds number is one, the dominant mechanism of heat transfer is$? |
| A. | Free convection |
| B. | Entry length problem in laminar forced conduction (developing thermal boundary layer) |
| C. | Mixed convection (both free and forced) |
| D. | Forced convection |
| Answer» D. Forced convection | |
| 371. |
The dimensionless group in mass transfer that is equivalent to Prandtl number in heat transfer is$? |
| A. | Nusselt number |
| B. | Sherwood number |
| C. | Schmidt number |
| D. | Stanton number |
| Answer» D. Stanton number | |
| 372. |
Correction is applied to LMTD for __________ flow.$? |
| A. | Parallel |
| B. | Counter |
| C. | Cross |
| D. | None of these |
| Answer» D. None of these | |
| 373. |
In a forward feed multiple effect evaporator, the pressure is$? |
| A. | Highest in last effect |
| B. | Lowest in last effect |
| C. | Same in all effects |
| D. | Dependent on the number of effects |
| Answer» C. Same in all effects | |
| 374. |
1000 Kg of liquid at 30°C in a well stirred vessel has to be heated to 120°C, using immersed coils carrying condensing steam at 150°C. The area of the steam coils is 1.2 m² and the overall heat transfer co-efficient to the liquid is 1500 W/m².°C. Assuming negligible heat loss to the surrounding and specific heat capacity of the liquid to be 4 kJ/kg.°C, the time taken for the liquid to reach desired temperature will be$? |
| A. | 15 min |
| B. | 22 min |
| C. | 44 min |
| D. | 51 min |
| Answer» E. | |
| 375. |
The ratio of the total emissive power to the absorptivity for all bodies is same at ther-mal equilibrium. This is __________ law.$? |
| A. | Kirchoffs |
| B. | Planck's |
| C. | Wien's displacement |
| D. | Stefan-Boltzman |
| Answer» B. Planck's | |
| 376. |
A tank painted with which of the following coloured paints, would heat up maximum by radiation from sun?$? |
| A. | Yellow paint |
| B. | White paint |
| C. | Black paint |
| D. | Grey paint |
| Answer» D. Grey paint | |
| 377. |
A body is called grey if the monochromatic emissivity of the body is$? |
| A. | Zero |
| B. | Unity |
| C. | Same for all wavelengths |
| D. | Different for all wavelengths |
| Answer» D. Different for all wavelengths | |
| 378. |
Stefen's block body radiation law can also be derived from __________ law.$? |
| A. | Kirchoffs |
| B. | Planck's |
| C. | Fourier's |
| D. | None of these |
| Answer» C. Fourier's | |
| 379. |
In the free convection regime of pool boiling, the heat flux is proportional to$? |
| A. | Δt1/2 |
| B. | Δt2 |
| C. | Δt5/4 |
| D. | Δt |
| Answer» D. ≈í√Æt | |
| 380. |
Conduction occurs in the buffer zone for a fluid flowing through a heated pipe, only when Prandtl number is$? |
| A. | 0.1 |
| B. | >1 |
| C. | < 1 |
| D. | L |
| Answer» B. >1 | |
| 381. |
In a single effect evaporator, the economy is$? |
| A. | 1 |
| B. | < 1 |
| C. | > 1 |
| D. | None of these |
| Answer» C. > 1 | |
| 382. |
Which type of heat exchanger is preferred for heavy heat loads?$? |
| A. | Double pipe |
| B. | Plate fine |
| C. | Series and parallel set of shell and tube |
| D. | None of these |
| Answer» D. None of these | |
| 383. |
Which of the following has the minimum absorptivity?$? |
| A. | Aluminium foil |
| B. | Coal dust |
| C. | Refractory bricks |
| D. | Iron plates |
| Answer» B. Coal dust | |
| 384. |
In forced circulation, the heating element is injected$? |
| A. | Internally |
| B. | Externally |
| C. | Both A and B |
| D. | Neither A nor B |
| Answer» B. Externally | |
| 385. |
LMTD for counterflow and prallel flow heat exchanger will be the same, when the$? |
| A. | Cold fluid is heated to a certain temperature by condensing steam (isothermal fluid) |
| B. | Outlent temperature of both the hot and cold fluid are same |
| C. | Outlet temperature of hot fluid is less than the outlet temperature of the cold fluid |
| D. | None of these |
| Answer» B. Outlent temperature of both the hot and cold fluid are same | |
| 386. |
In a shell and tube heat exchanger, square pitch compared to triangular pitch$? |
| A. | Gives a higher shell side pressure drop |
| B. | Gives a lower shell side pressure drop |
| C. | Can pack more surface area into a shell of given diameter |
| D. | None of these |
| Answer» B. Gives a lower shell side pressure drop | |
| 387. |
Electromagnetic radiations propagate in vacuum with a velocity of __________ metre/second.$? |
| A. | 3 x l05 |
| B. | 3 x l08 |
| C. | 3 x l010 |
| D. | 3 x l012 |
| Answer» C. 3 x l010 | |
| 388. |
For a fluid flowing in an annulus space, the wetted perimeter for heat transfer and pressure drop are$? |
| A. | Same |
| B. | Different |
| C. | Never different |
| D. | Linearly related |
| Answer» C. Never different | |
| 389. |
jH factor for heat transfer is not a function of the __________ number.$? |
| A. | Reynolds |
| B. | Nusselt |
| C. | Grashoff |
| D. | Both B & C |
| Answer» E. | |
| 390. |
Thickness of thermal boundary layer is more compared to that of hydrodynamic boundary layer, when the value of Prandtl number is$? |
| A. | 1 |
| B. | < 1 |
| C. | > 1 |
| D. | > 5 |
| Answer» C. > 1 | |
| 391. |
When warm and cold liquids are mixed, the heat transfer is mainly by$? |
| A. | Conduction |
| B. | Convection |
| C. | Radiation |
| D. | Both A & C |
| Answer» C. Radiation | |
| 392. |
Overall thermal resistance for conductive heat transfer through a series of flat resistances is equal to the$? |
| A. | Maximum resistance in the series |
| B. | Sum of all resistances |
| C. | Average of all resistances |
| D. | Minimum resistance presents in the series |
| Answer» C. Average of all resistances | |
| 393. |
The purpose of providing expansion bellows in the shell of tubular exchanger is to$? |
| A. | Increase the heating load |
| B. | Impart structural strength |
| C. | Account for the uneven expansion of shell and tube bundles |
| D. | Facilitate increase of shell length, if needed |
| Answer» D. Facilitate increase of shell length, if needed | |
| 394. |
Which of the following parameters is increased by use of finned tube in a multipass shell and tube heat exchanger?$? |
| A. | Tube side pressure drop and the heat transfer rate |
| B. | Convective heat transfer co-efficient |
| C. | Effective tube surface area for convective heat transfer |
| D. | All of the above |
| Answer» E. | |
| 395. |
__________ paint has the minimum absorption co-efficient.$? |
| A. | Black |
| B. | White lead |
| C. | Grey |
| D. | Light cream |
| Answer» C. Grey | |
| 396. |
Thermal diffusivity of a material$? |
| A. | Has the unit m² /sec |
| B. | Is defined as K/ρ . Cp |
| C. | Is the ratio of thermal conductivity to thermal capacity |
| D. | All of the above |
| Answer» E. | |
| 397. |
In a forward feed multiple effect evaporator unit$? |
| A. | Viscosity of liquid is highest in first effect |
| B. | Transfer from effect to effect is done by pumps |
| C. | No pump is required to withdraw the product from the last effect |
| D. | None of these |
| Answer» E. | |
| 398. |
The Nusselt number for fully developed (both thermally and hydrodynamically) laminar flow through a circular pipe whose surface temperature remains constant is$? |
| A. | 1.66 |
| B. | 88.66 |
| C. | 3.66 |
| D. | Dependent on NRe only |
| Answer» D. Dependent on NRe only | |
| 399. |
A multiple effect evaporator has a capacity to process 4000 kg of solid caustic soda per day, when it is concentrating from 10% to 25% solids. The water evaporated in kg per day is$? |
| A. | 6000 |
| B. | 24000 |
| C. | 60000 |
| D. | 48000 |
| Answer» C. 60000 | |
| 400. |
Evaporation by thermocompression results in the$? |
| A. | Saving of steam |
| B. | Realisation of multiple effect economy in a single effect |
| C. | Both A and B |
| D. | None of these |
| Answer» D. None of these | |