MCQOPTIONS
Saved Bookmarks
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.
| 151. |
Nusselt number is the ratio of the ____________________? |
| A. | Temperature gradient of the wall to that across the entire pipe |
| B. | Temperature difference to the temperature gradient at the wall |
| C. | Heat flux at the wall to that across the entire pipe |
| D. | None of these |
| Answer» D. None of these | |
| 152. |
Nusselt number is the ratio of the temperature gradient at the wall to_________________? |
| A. | Temperature difference |
| B. | Heat flux |
| C. | That across the entire pipe |
| D. | None of these |
| Answer» D. None of these | |
| 153. |
Nusselt number is a function of Prandtl number and ______________ number of fluid in natural convection heat transfer? |
| A. | Grashoff |
| B. | Biot |
| C. | Stanton |
| D. | Reynolds |
| Answer» B. Biot | |
| 154. |
Nusselt number (for forced convection heat transfer) is a function of the _____________ number? |
| A. | Prandtl |
| B. | Reynolds |
| C. | Both A. & B. |
| D. | Neither A. nor B. |
| Answer» C. Both A. & B. | |
| 155. |
Nucleate boiling is promoted ___________________? |
| A. | On polished surfaces |
| B. | On rough surfaces |
| C. | In the absence of agitation |
| D. | None of these |
| Answer» C. In the absence of agitation | |
| 156. |
Natural convection is characterised by__________________? |
| A. | Grashoff number |
| B. | Peclet number |
| C. | Reynolds number |
| D. | Prandtl number |
| Answer» B. Peclet number | |
| 157. |
Multiple effect evaporators are commonly used in the manufacture of P. Paper Q. Superphosphate R. Sugar S. Fats ? |
| A. | P and Q |
| B. | P and R |
| C. | P and S |
| D. | R and S |
| Answer» D. R and S | |
| 158. |
Multiple effect evaporators ar used to___________________? |
| A. | Increase the steam economy & decrease the capacity |
| B. | Increase the steam economy & the capacity |
| C. | Decrease the steam economy & the capacity |
| D. | Decrease the steam economy & increase the capacity |
| Answer» C. Decrease the steam economy & the capacity | |
| 159. |
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 | |
| 160. |
Multiple effect evaporation accounts for___________________? |
| A. | Steam economy |
| B. | Lower operating costs |
| C. | Investment economy |
| D. | None of these |
| Answer» B. Lower operating costs | |
| 161. |
Multipass heat exchangers are used______________________? |
| A. | Because of simplicity of fabrication |
| B. | For low heat load |
| C. | To obtain higher heat transfer co-efficient and shorter tube |
| D. | To reduce the pressure drop |
| Answer» D. To reduce the pressure drop | |
| 162. |
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 | |
| 163. |
Mode of heat transfer in which the fluid moves under the influence of changes in fluid pressure produced by external work is called_______________? |
| A. | Radiation |
| B. | Natural convection |
| C. | Forced convection |
| D. | Conduction |
| Answer» D. Conduction | |
| 164. |
Minimum recommended baffle spacing in a shell and tube heat exchanger is about (where, D = shell diameter)? |
| A. | 0.2 D |
| B. | 0.5 D |
| C. | 0.66 D |
| D. | 0.80 D |
| Answer» B. 0.5 D | |
| 165. |
Maximum water velocity in tubes of a 1-2 shell and tube heat exchanger may be around _____________ metres/second? |
| A. | 1 |
| B. | 10 |
| C. | 20 |
| D. | 30 |
| Answer» B. 10 | |
| 166. |
Maximum heat transfer rate is obtained in ______________ flow? |
| A. | Laminar |
| B. | Turbulent |
| C. | Creeping |
| D. | Transition region |
| Answer» C. Creeping | |
| 167. |
Maximum heat transfer rate is achieved in _____________ flow? |
| A. | Co-current |
| B. | Counter-current |
| C. | Turbulent |
| D. | Laminar |
| Answer» D. Laminar | |
| 168. |
Maximum heat transfer rate can be expected in case of_________? |
| A. | Laminar flow |
| B. | Co-current flow |
| C. | Turbulent flow |
| D. | Heat flow rate is independent of nature of flow |
| Answer» D. Heat flow rate is independent of nature of flow | |
| 169. |
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 | |
| 170. |
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 | |
| 171. |
Loss of heat from untagged steam pipe to the ambient air is by __________________? |
| A. | Conduction |
| B. | Convection |
| C. | Radiation |
| D. | All A., B. & C. |
| Answer» E. | |
| 172. |
Log mean temperature difference (LMTD) cannot be used, if ___________________? |
| A. | Heat transfer co-efficient over the entire heat exchanger is not constant |
| B. | There exists an unsteady state |
| C. | The heat capacity is not constant and there is a phase change |
| D. | None of these |
| Answer» E. | |
| 173. |
LMTD for evaporators & condensers for a given terminal parameters & set of conditions for counter-flow is equal to that for parallel flow. In such heat exchangers, with one of the fluids condensing or evaporating, the surface area required is the least in the ______________ flow? |
| A. | Parallel |
| B. | Mixed |
| C. | Counter flow |
| D. | Same in either A , B. or C. |
| Answer» E. | |
| 174. |
LMTD for counter-flow and parallel flow heat exchanger will be the same, when the_________________? |
| A. | Cold fluid is heated to a certain temperature by condensing steam (isothermal fluid) |
| B. | Outlet 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. Outlet temperature of both the hot and cold fluid are same | |
| 175. |
LMTD correction factor which is to be applied for a cross-flow heat exchanger increases with increase in the number of shell passes. Its value for a single pass cross flow heat exchanger is __________________? |
| A. | 0 |
| B. | 1 |
| C. | > 1 |
| D. | < 1 |
| Answer» E. | |
| 176. |
LMTD can’t be used as such without a correction factor for the_________________? |
| A. | Multipass heat exchanger |
| B. | Baffled heat exchanger |
| C. | Condensation of mixed vapour in a condenser |
| D. | All A. B. and C. |
| Answer» E. | |
| 177. |
Leidenfrost point is a term concerned with the____________________? |
| A. | Condensation of the saturated vapor on a cold surface |
| B. | Concentration of a corrosive solution by evaporation |
| C. | Heat transfer between two highly viscous liquids |
| D. | Boiling of a liquid on a hot surface |
| Answer» E. | |
| 178. |
Latent heat absorbed by 1 lb of water at 212°F, when it is changed to steam at 212°F, may be around ______________ BTU? |
| A. | 180 |
| B. | 970 |
| C. | 3.97 |
| D. | None of these |
| Answer» B. 970 | |
| 179. |
Kirchoff’s law is applicable to________________? |
| A. | Monochromatic radiation only |
| B. | Total radiation only |
| C. | Both A. and B. |
| D. | Only volumes and not to surfaces |
| Answer» D. Only volumes and not to surfaces | |
| 180. |
Kirchoff‟s law applies to _____________ radiation? |
| A. | Total |
| B. | Monochromatic |
| C. | Both A. & B. |
| D. | Neither A. nor B. |
| Answer» D. Neither A. nor B. | |
| 181. |
Kg of liquid evaporated per hour in an evaporator is defined as its_________________? |
| A. | Capacity |
| B. | Economy |
| C. | Steam load |
| D. | None of these |
| Answer» B. Economy | |
| 182. |
jH factor for heat transfer is not a function of the _______________ number? |
| A. | Reynolds |
| B. | Nusselt |
| C. | Grashoff |
| D. | Both B. & C. |
| Answer» E. | |
| 183. |
jH factor for heat transfer depends upon the ____________ number? |
| A. | Biot |
| B. | Nusselt |
| C. | Reynolds |
| D. | Prandtl |
| Answer» D. Prandtl | |
| 184. |
It is not recommended to use a 1-2 shell and tube heat exchanger for a particular heat duty, whenever the LMTD correction factor is___________________? |
| A. | > 0.75 |
| B. | < 0.75 |
| C. | < 0.50 |
| D. | < 0.25 |
| Answer» C. < 0.50 | |
| 185. |
It is not preferable to use superheated steam in evaporators, because of its very_________________? |
| A. | High temperature |
| B. | High pressure |
| C. | Low film co-efficient |
| D. | None of these |
| Answer» D. None of these | |
| 186. |
It is desired to concentrate a 20% salt solution (20 kg of salt in 100 kg of solution) to a 30% salt solution in an evaporator. Consider a feed of 300 kg/min at 30°C. The boiling point of the solution is 110°C, the latent heat of vaporisation is 2100 kJ/kg and the specific heat of the solution is 4 kJ/kg.K. The rate at which the heat has to be supplied in (kJ/min) to the evaporator is____________________? |
| A. | 3.06 × 105 |
| B. | 6.12 × 105 |
| C. | 7.24 × 105 |
| D. | 9.08 × 105 |
| Answer» B. 6.12 × 105 | |
| 187. |
Intermittent tube cleaning is possible to be done in case of a _____________ evaporator? |
| A. | Basket type |
| B. | Horizontal tube |
| C. | Calandria |
| D. | None of these |
| Answer» B. Horizontal tube | |
| 188. |
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 | |
| 189. |
Increasing the liquor level in the evaporator results in the_______________? |
| A. | Increasing the liquor level in the evaporator results in the_______________? |
| B. | Increase in liquor film co-efficient |
| C. | Decreased effect of hydrostatic head |
| D. | Increased true temperature drop |
| Answer» B. Increase in liquor film co-efficient | |
| 190. |
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. Δt | |
| 191. |
In the equation Q = UAΔt; Δt is_________________________? |
| A. | Geometric mean temperature difference |
| B. | Arithmetic mean temperature difference |
| C. | Logarithmic mean temperature difference |
| D. | The difference of average bulk temperatures of hot and cold fluids |
| Answer» D. The difference of average bulk temperatures of hot and cold fluids | |
| 192. |
In sub-cooled boiling ? |
| A. | Temperature of the heating surface is less than the boiling point of the liquid |
| B. | Temperature of the heating surface is more than the boiling point of the liquid |
| C. | Bubbles from heating surface are absorbed by the mass of the liquid |
| D. | Very large vapour space is necessary |
| Answer» C. Bubbles from heating surface are absorbed by the mass of the liquid | |
| 193. |
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/m2. °K | |
| 194. |
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/m2°K | |
| 195. |
In regenerative air preheater (as practised in heating of coke ovens), the heat is transferred_________________? |
| A. | Through a metallic wall |
| B. | By direct contact of hot flue gas with air |
| C. | By heating an intermediate material (like chequor bricks) and then heating the air from this hot material |
| D. | None of these |
| Answer» D. None of these | |
| 196. |
In pipe flow, heat is transferred from hot wall to the liquid by__________________? |
| A. | Conduction only |
| B. | Forced convection only |
| C. | Forced convection and conduction |
| D. | Free and forced convection |
| Answer» D. Free and forced convection | |
| 197. |
In natural convection heat transfer, the correlating parameter is the_______________________? |
| A. | Graetz number |
| B. | Eckert number |
| C. | Grashoff number |
| D. | Bond number |
| Answer» D. Bond number | |
| 198. |
In Joule’s experiment, an insulated container contains 20 kg of water initially at 25°C. It is stirred by an agitator, which is made to turn by a slowly falling body weighing 40 kg through a height of 4 m. The process is repeated 500 times. The acceleration due to gravity is 9.8 ms-2. Neglecting the heat capacity of agitator, the temperature of water (in °C) is________________? |
| A. | 40.5 |
| B. | 34.4 |
| C. | 26.8 |
| D. | 25 |
| Answer» C. 26.8 | |
| 199. |
In Fourier’s law, the proportionality constant is called the______________________? |
| A. | Heat transfer co-efficient |
| B. | Thermal diffusivity |
| C. | Thermal conductivity |
| D. | Stefan-Boltzmann constant |
| Answer» D. Stefan-Boltzmann constant | |
| 200. |
In forced convection, the Nusselt number is a function of ____________________? |
| A. | Re and Pr |
| B. | Re and Gr |
| C. | Pr and Gr |
| D. | Re and Sc |
| Answer» B. Re and Gr | |