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.
| 201. |
In forced convection, the heat transfer depends on _______________? |
| A. | Re, Pr |
| B. | Re, Gr |
| C. | Mainly Gr |
| D. | Re only |
| Answer» B. Re, Gr | |
| 202. |
In forced circulation, the heating element is injected_________________? |
| A. | Internally |
| B. | Externally |
| C. | Both A. and A. |
| D. | Neither A. nor B. |
| Answer» B. Externally | |
| 203. |
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 | |
| 204. |
In counter flow compared to parallel flow, ? |
| A. | LMTD is greater |
| B. | Less surface area is required for a given heat transfer rate |
| C. | Both A. and B. |
| D. | More surface area is required for a given heat transfer rate |
| Answer» D. More surface area is required for a given heat transfer rate | |
| 205. |
In case of vertical tube evaporator, with increase in liquor level, the overall heat transfer co-efficient______________? |
| A. | Increases |
| B. | Decreases |
| C. | Is not affected |
| D. | May increase or decrease; depends on the feed |
| Answer» C. Is not affected | |
| 206. |
In case of surface condensers, a straight line is obtained on plotting 1/U vs. ____________ on an ordinary graph paper? |
| A. | 1/V̅ -0.8 |
| B. | V̅ -0.8 |
| C. | V̅ -2 |
| D. | 1/ V̅ -2 |
| Answer» B. V̅ -0.8 | |
| 207. |
In case of parallel flow heat exchanger, the lowest temperature theoretically attainable by the hot fluid is _____________ the outlet temperature of the cold fluid? |
| A. | Equal to |
| B. | More than |
| C. | Less than |
| D. | Either more or less than (depending upon the fluid) |
| Answer» B. More than | |
| 208. |
In case of heat transfer by conduction in a hollow cylinder, ______________ mean area is used to calculate the heat transfer rate? |
| A. | Geometric |
| B. | Arithmetic |
| C. | Logarithmic |
| D. | Either A., B. or C. |
| Answer» D. Either A., B. or C. | |
| 209. |
In case of heat flow by conduction for a cylindrical body with an internal heat source, the nature of temperature distribution is_________________? |
| A. | Linear |
| B. | Hyperbolic |
| C. | Parabolic |
| D. | None of these |
| Answer» D. None of these | |
| 210. |
In case of evaporators, liquid entrainment results primarily due to_________________? |
| A. | High vacuum in the evaporator |
| B. | High evaporation rate |
| C. | Foaming of the solution |
| D. | High heat transfer rate |
| Answer» D. High heat transfer rate | |
| 211. |
In case of _______________ boiling, the liquid temperature is below the saturation temperature and the boiling takes place in the vicinity of the heated surface? |
| A. | Nucleate |
| B. | Local |
| C. | Pool |
| D. | Saturated |
| Answer» C. Pool | |
| 212. |
In case of _____________ boiling, the bubbles formed on a submerged hot surface get absorbed in the mass of the liquid? |
| A. | Nucleate |
| B. | Pool |
| C. | Low pressure |
| D. | None of these |
| Answer» C. Low pressure | |
| 213. |
In case of a vertical tube evaporator, with increase in the liquor level, the___________________? |
| A. | Capacity of the evaporator is decreased |
| B. | Capacity of the evaporator is increased |
| C. | True temperature drop increases |
| D. | Both B. and C. |
| Answer» B. Capacity of the evaporator is increased | |
| 214. |
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. | |
| 215. |
In case of a super-cooled solution, which is on the verge of crystallisation, the free energy of the solution as compared to that of the solid is ________________? |
| A. | More |
| B. | Less |
| C. | Same |
| D. | More or less; depends on the nature of solution |
| Answer» B. Less | |
| 216. |
In case of a shell and tube heat exchanger, the minimum and maximum baffle spacing is respectively (where, D = inside diameter of the shell) ? |
| A. | D/5 and D |
| B. | D/2 and 2 D |
| C. | D/4 and 2 D |
| D. | D and 2 D |
| Answer» B. D/2 and 2 D | |
| 217. |
In case of a multipass shell and tube heat exchanger, the temperature drop in the fluid _______________? |
| A. | Is inversely proportional to the resistance across which the drop occurs |
| B. | And the wall are proportional to individual resistances |
| C. | And the wall is not related |
| D. | None of these |
| Answer» C. And the wall is not related | |
| 218. |
In case of a multipass shell and tube heat exchanger, providing a baffle on the shell side ______________ the heat transfer rate? |
| A. | Increases |
| B. | Decreases |
| C. | Does not affect |
| D. | May increase or decrease, depends on the type of baffle |
| Answer» B. Decreases | |
| 219. |
In Biot number, the characteristic length used is the ratio of the _______________ of the solid? |
| A. | Volume to surface area |
| B. | Perimeter to surface area |
| C. | Surface area to volume |
| D. | Surface area to perimeter |
| Answer» B. Perimeter to surface area | |
| 220. |
In an interphase heat transfer process, the equilibrium state corresponds to equality of temperature in the two phases, while the condition for equilibrium in an interphase mass transfer process is equality of___________________? |
| A. | Concentrations |
| B. | Chemical potentials |
| C. | Activity co-efficients |
| D. | Mass transfer co-efficients |
| Answer» B. Chemical potentials | |
| 221. |
In an extended surface heat exchanger, fluid having lower co-efficient________________? |
| A. | Flows through the tube |
| B. | Flows outside the tubes |
| C. | Can flow either inside or outside the tubes |
| D. | Should not be used as it gives very high pressure drop |
| Answer» C. Can flow either inside or outside the tubes | |
| 222. |
In a single evaporator system, the steam economy ________________ by creating vacuum in the evaporator? |
| A. | Increases |
| B. | Decreases |
| C. | Remain constant |
| D. | May increase or decrease, depends on the vacuum |
| Answer» B. Decreases | |
| 223. |
In a single effect evaporator, the economy is________________? |
| A. | 1 |
| B. | < 1 |
| C. | > 1 |
| D. | None of these |
| Answer» C. > 1 | |
| 224. |
In a shell and tube type heat exchanger, the floating tube bundle heat arrangement is used________________? |
| A. | In low range of temperature differences |
| B. | In high range of temperature differences |
| C. | Because of its low cost |
| D. | To prevent corrosion of the tube bundles |
| Answer» C. Because of its low cost | |
| 225. |
In a shell and tube heat exchanger, the tube side heat transfer co-efficient just at the entrance of the tube is_________________? |
| A. | Infinity |
| B. | Zero |
| C. | Same as average heat transfer co-efficient for tube side |
| D. | None of these |
| Answer» B. Zero | |
| 226. |
In a shell and tube heat exchanger, the shell side fluid velocity can‟t be changed by changing the_________________? |
| A. | Tube layout |
| B. | Tube diameter |
| C. | Tube pitch |
| D. | Number of baffles |
| Answer» C. Tube pitch | |
| 227. |
In a shell and tube heat exchanger, the height of 25 percent cut baffles is equal to (where, D = inside diameter of shell) ? |
| A. | 0.25 D |
| B. | 0.50 D |
| C. | 0.75 D |
| D. | None of these |
| Answer» D. None of these | |
| 228. |
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 | |
| 229. |
In a shell and tube heat exchanger, putting a longitudinal baffle across the shell, forces the shell side fluid to pass _____________ through the heat exchanger ? |
| A. | Once |
| B. | Twice |
| C. | Thrice |
| D. | Four times |
| Answer» C. Thrice | |
| 230. |
In a shell and tube heat exchanger, floating head is used for _________________? |
| A. | Large temperature differentials |
| B. | High heat transfer co-efficient |
| C. | Low pressure drop |
| D. | Less corrosion of tubes |
| Answer» B. High heat transfer co-efficient | |
| 231. |
In a parallel flow heat exchanger, if the outlet temperature of hot and cold fluids are the same, then the log mean temperature difference (LMTD) is_________________? |
| A. | Minimum |
| B. | Maximum |
| C. | Zero |
| D. | Infinity |
| Answer» D. Infinity | |
| 232. |
In a multiple effect evaporator, the effect of boiling point elevation is to______________________? |
| A. | Reduce the capacity |
| B. | Reduce the economy |
| C. | Increase the economy |
| D. | None of these |
| Answer» B. Reduce the economy | |
| 233. |
In a multipass shell and tube heat exchanger, tube side return pressure loss is equal to _____________ the velocity head? |
| A. | Twice |
| B. | Four times |
| C. | Square root of |
| D. | Square of |
| Answer» C. Square root of | |
| 234. |
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. | ∞ |
| Answer» B. > 1 | |
| 235. |
In a laboratory test run, the rate of drying was found to be 0.5 x 10-3 kg/m2.s, when the moisture content reduced from 0.4 to 0.1 on dry basis. The critical moisture content of the material is 0.08 on a dry basis. A tray dryer is used to dry 100 kg (dry basis) of the same material under identical conditions. The surface area of the material is 0.04 m2/kg of dry solid. The time required (in seconds) to reduce the moisture content of the solids from 0.3 to 0.2 (dry basis) is______________________? |
| A. | 2000 |
| B. | 4000 |
| C. | 5000 |
| D. | 6000 |
| Answer» D. 6000 | |
| 236. |
In a heat exchanger, the rate of heat transfer from the hot fluid to the cold fluid___________________? |
| A. | Varies directly as the area and the LMTD |
| B. | Directly proportional to LMTD and inversely proportional to the area |
| C. | Varies as square of the area |
| D. | None of these |
| Answer» B. Directly proportional to LMTD and inversely proportional to the area | |
| 237. |
In a heat exchanger, floating head is provided to____________________? |
| A. | Facilitate cleaning of the exchanger |
| B. | Increase the heat transfer area |
| C. | Relieve stresses caused by thermal expansion |
| D. | Increase log mean temperature gradient |
| Answer» D. Increase log mean temperature gradient | |
| 238. |
In a heat exchanger, one transfer unit means___________________? |
| A. | A section of the exchanger in which change in temperature of one stream equals the average driving force in the section |
| B. | The size of the exchanger in which heat transfer rate is 1 kcal/hr |
| C. | Both A. and B. |
| D. | None of these |
| Answer» B. The size of the exchanger in which heat transfer rate is 1 kcal/hr | |
| 239. |
In a gas-liquid shell and tube heat exchanger, the_________________? |
| A. | Presence of a non-condensable gas decreases the condensing film co-efficient |
| B. | Gases under high pressure are routed through the tube side, because high pressure gases are corrosive in nature |
| C. | Gases to be heated/cooled is normally routed through the shell side, because the corrosion caused by the cooling water or steam condensate remain loca |
| D. | All A, B. & C. |
| Answer» E. | |
| 240. |
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 | |
| 241. |
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. | |
| 242. |
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 | |
| 243. |
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 | |
| 244. |
In a co-current double pipe heat exchanger used for condensing saturated steam over the inner tube, if the entrance and exit conditions of the coolant are interchanged, then the rate of condensation will___________________? |
| A. | Increase |
| B. | Decrease |
| C. | Remain unchanged |
| D. | Either increase or decrease; depends on the coolant flow rate |
| Answer» D. Either increase or decrease; depends on the coolant flow rate | |
| 245. |
In a boiling curve, the peak heat flux is called the _____________ point? |
| A. | Nusselt |
| B. | Leidenfrost |
| C. | Boiling |
| D. | Burnout |
| Answer» C. Boiling | |
| 246. |
In a backward feed multiple effect evaporator ___________________ ? |
| A. | Feed is introduced in the first effect |
| B. | Feed flows from low pressure to high pressure |
| C. | No pumps are required between successive effects |
| D. | None of these |
| Answer» C. No pumps are required between successive effects | |
| 247. |
In a 1-1 concurrent heat exchanger, if the tube side fluid outlet temperature is equal to the shell side fluid outlet temperature, then the LMTD is_________________? |
| A. | ∞ |
| B. | 0 |
| C. | Equal to the difference between hot and cold fluids inlet temperature |
| D. | Equal to the difference between hot fluid inlet temperature and cold fluid outlet temperature |
| Answer» C. Equal to the difference between hot and cold fluids inlet temperature | |
| 248. |
If the thermal conductivity of a wall material is independent of temperature, the steady state temperature distribution in the very large thin plane wall having steady, uniform surface temperature follows ____________ law? |
| A. | Hyperbolic |
| B. | Parabolic |
| C. | Linear |
| D. | Logarithmic |
| Answer» D. Logarithmic | |
| 249. |
If the thermal conductivity of a wall material is independent of temperature, the steady state temperature distribution in the very large thin plane wall having steady, uniform surface temperature follows _____________ law? |
| A. | Parabolic |
| B. | Hyperbolic |
| C. | Linear |
| D. | Logarithmic |
| Answer» B. Hyperbolic | |
| 250. |
If the baffle spacing in a shell and tube heat exchanger increases, then the Reynolds number of the shell side fluid_________________? |
| A. | Remains unchanged |
| B. | Increases |
| C. | Increases or decreases depending on number of shell passes |
| D. | Decreases |
| Answer» E. | |