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.
| 101. |
The equivalent diameter for pressure drop is ________________ that for heat transfer? |
| A. | Smaller than |
| B. | Greater than |
| C. | Equal to |
| D. | Not related with |
| Answer» B. Greater than | |
| 102. |
The equation, (NSt × N2/3 Pr) = f/2, is the ____________ analogy ? |
| A. | Colburn |
| B. | Reynolds |
| C. | Prandtl |
| D. | None of these |
| Answer» B. Reynolds | |
| 103. |
The equation, Nst = (f/2)/[1 + 5 (Npr – 1) √(f/2)], corresponds to ______________ analogy? |
| A. | Von-Karman |
| B. | Reynolds |
| C. | Colburn |
| D. | Prandtl |
| Answer» E. | |
| 104. |
The equation, Nst = f/2, is the _____________ analogy? |
| A. | Colburn |
| B. | Reynolds |
| C. | Prandtl |
| D. | None of these |
| Answer» C. Prandtl | |
| 105. |
The energy radiated from a surface Q at absolute temperature T is related as__________________? |
| A. | Q ∝ T2 |
| B. | Q ∝ T4 |
| C. | Q ∝ T3 |
| D. | None of these |
| Answer» C. Q ∝ T3 | |
| 106. |
The driving potential for the crystal growth during crystallisation is the _______________ of the solution? |
| A. | Concentration |
| B. | Viscosity |
| C. | Super-saturation |
| D. | Density |
| Answer» D. Density | |
| 107. |
The Dittus-Boelter equation for convective heat transfer [(i.e. h = 0.023 (K/D) (Re)0.8 (Pr)0.4] cannot be used for________________? |
| A. | Low Reynold’s number |
| B. | Very low Grashoff number |
| C. | Molten metals |
| D. | All A., B. and C. |
| Answer» E. | |
| 108. |
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 | |
| 109. |
The critical radius ‘r’ of insulation on a pipe is given by____________________? |
| A. | r = 2k/h |
| B. | r = k/h |
| C. | r = k/2h |
| D. | r = h/k |
| Answer» C. r = k/2h | |
| 110. |
The critical radius of insulation for cylindrical pipe is (where, hi = heat transfer coefficient at inside of the pipe) ? |
| A. | K/h0 |
| B. | 2K/h0 |
| C. | hi/K |
| D. | 2hi/K |
| Answer» B. 2K/h0 | |
| 111. |
The critical radius of insulation for a spherical shell is (where, K = thermal conductivity of insulating material h0 = heat transfer coefficient at the outer surface) ? |
| A. | K/h0 |
| B. | 2K/h0 |
| C. | h0/K |
| D. | h0/2K |
| Answer» C. h0/K | |
| 112. |
The characteristic dimensionless groups for heat transfer to a fluid flowing through a pipe in laminar flow are_______________? |
| A. | Re.Gz |
| B. | Nu, Pr |
| C. | Nu, Pr, Re |
| D. | Nu, Gz |
| Answer» E. | |
| 113. |
The capacity of double-effect evaporator is less than half of the capacity of two single effects, each of which is operating over same terminal temperature difference, when the________________ ? |
| A. | Solution has an elevation of boiling point |
| B. | Evaporators operate under vacuum |
| C. | Evaporators operate at atmospheric pressure |
| D. | None of these |
| Answer» B. Evaporators operate under vacuum | |
| 114. |
The advantage of using a 1 – 2 shell and tube heat exchanger over a 1 – 1 shell and tube heat exchanger is_________________? |
| A. | Lower tube side pressure drop |
| B. | Lower shell side pressure drop |
| C. | Higher tube side heat transfer co-efficient |
| D. | Higher shell side heat transfer co-efficient |
| Answer» D. Higher shell side heat transfer co-efficient | |
| 115. |
The advantage of backward feed multiple effect evaporators over forward feed units is that___________________? |
| A. | Heat sensitive material can be handled |
| B. | There is no additional cost of pumping |
| C. | Most concentrated liquid is at highest temperature |
| D. | Equal heat transfer co-efficients exist in various effects |
| Answer» D. Equal heat transfer co-efficients exist in various effects | |
| 116. |
The actual temperature drop across the heating surface in an evaporator depends on the_________________? |
| A. | Feed |
| B. | Depth of liquid over heating surface |
| C. | Pressure difference between steam chest and vapour space |
| D. | All A., B. and C. |
| Answer» E. | |
| 117. |
The actual temperature drop across the heating surface of an evaporator depends on the_______________? |
| A. | Liquid depth over the heating surface |
| B. | Solution being evaporated |
| C. | Pressure difference between the steam chest and the vapor space above the boiling liquid |
| D. | All A., B. and C. |
| Answer» E. | |
| 118. |
The absorptivity of a grey body at a given temperature _____________ with increasing wavelength of radiation? |
| A. | Increases |
| B. | Decreases |
| C. | Remain constant |
| D. | May increase or decrease; depends on the material |
| Answer» E. | |
| 119. |
The absorptivity of a body is equal to its emissivity _________________? |
| A. | At a particular temperature |
| B. | For circular bodies |
| C. | Under thermal equilibrium |
| D. | None of these |
| Answer» D. None of these | |
| 120. |
Reynold’s analogy states that_________________? |
| A. | Nst α f |
| B. | Nst α NRe |
| C. | NNu α f |
| D. | NRe α f |
| Answer» B. Nst α NRe | |
| 121. |
Reynold’s analogy states that (where, St = Stanton number f = friction factor) ? |
| A. | St = f/2 |
| B. | St = f/4 |
| C. | St = 4f |
| D. | St = f1/2 |
| Answer» B. St = f/4 | |
| 122. |
Resistance to heat flow by conduction is proportional to (where, t & ρ are thickness & density of the material respectively and A = area normal to the direction of heat flow.) ? |
| A. | t |
| B. | 1/ρ |
| C. | 1/A |
| D. | All A., B. & C. |
| Answer» E. | |
| 123. |
Removal of ______________ heat is involved in the condensation of a vapor under saturated conditions? |
| A. | Super |
| B. | Sensible |
| C. | Latent |
| D. | Both B. & C. |
| Answer» C. Latent | |
| 124. |
Reason for operating an evaporator in multiple effects is to secure ___________________? |
| A. | Increased steam economy |
| B. | Decreased steam consumption |
| C. | Both A. and B. |
| D. | Increased capacity |
| Answer» D. Increased capacity | |
| 125. |
Rate of heat transfer by vaporisation from pools of water is affected by the ____________________? |
| A. | Nature of heating surface and distribution of bubbles |
| B. | Surface tension of water |
| C. | Viscosity of water |
| D. | All A., B. and C. |
| Answer» E. | |
| 126. |
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. | |
| 127. |
Radiation heat losses from satisfactorily insulated high pressure boiler may be about _____________ percent? |
| A. | 1 |
| B. | 7 |
| C. | 18 |
| D. | 26 |
| Answer» C. 18 | |
| 128. |
Radiation energy is emitted by all the substances, which are above____________________? |
| A. | 0°K |
| B. | 0°C |
| C. | 100°C |
| D. | Room temperature |
| Answer» B. 0°C | |
| 129. |
Radiation heat transfer rates does not depend upon the_________________? |
| A. | Type of absorbing surface |
| B. | Distance between the heat source and the object receiving the heat |
| C. | Surface area and temperature of the heat source |
| D. | None of these |
| Answer» E. | |
| 130. |
Radiant energy received by a body is proportional to (where, d = the distance between the object emitting radiation and that receiving it.) ? |
| A. | √d |
| B. | d |
| C. | d2 |
| D. | d1.5 |
| Answer» D. d1.5 | |
| 131. |
Presence of a non-condensing gas in a condensing vapour___________________? |
| A. | Increases the rate of condensation |
| B. | Decreases thermal resistance |
| C. | Is desirable to increase the film co-efficient |
| D. | None of these |
| Answer» E. | |
| 132. |
Prandtl number is the reciprocal of____________________? |
| A. | Thermal diffusivity/Momentum diffusivity |
| B. | Thermal diffusivity × Momentum |
| C. | Thermal diffusivity × Mass diffusivity |
| D. | Mass diffusivity × Momentum diffusivity |
| Answer» B. Thermal diffusivity × Momentum | |
| 133. |
Prandtl number is the ratio of________________? |
| A. | Momentum diffusivity to mass diffusivity |
| B. | Momentum diffusivity to thermal diffusivity |
| C. | Thermal diffusivity to mass diffusivity |
| D. | Thermal diffusivity to momentum diffusivity |
| Answer» C. Thermal diffusivity to mass diffusivity | |
| 134. |
Prandtl number is given by__________________? |
| A. | CP μ/a |
| B. | hD/k |
| C. | CP μ/k |
| D. | μ/h CP |
| Answer» D. μ/h CP | |
| 135. |
Prandtl and Reynolds analogy are same, when Prandtl number is____________________? |
| A. | 0.5 |
| B. | 1 |
| C. | > 2 |
| D. | 1.5 |
| Answer» C. > 2 | |
| 136. |
Prandtl number for most of dry gases is about________________? |
| A. | 0.001 |
| B. | 0.72 |
| C. | 70 |
| D. | 150 |
| Answer» C. 70 | |
| 137. |
Prandtl and Reynold’s analogies are identical for Prandtl number value of__________________? |
| A. | 0 |
| B. | 0.5 |
| C. | 1 |
| D. | 5 |
| Answer» D. 5 | |
| 138. |
Planck’s distribution law is valid for _____________ bodies? |
| A. | Black |
| B. | White |
| C. | Coloured |
| D. | All A., B. & C. |
| Answer» D. All A., B. & C. | |
| 139. |
Pick out the wrong statement/ |
| A. | The emissivity of a surface decreases, if it gets corroded by atmospheric environment |
| B. | The emissivity of a surface increases with increase in surface roughness |
| C. | The emissivity of a polished surface is quite low |
| D. | The emissivity of a non-metallic surface decreases with increase in the temperature |
| Answer» B. The emissivity of a surface increases with increase in surface roughness | |
| 140. |
Pick out the correct equation ? |
| A. | jH = (St)(Pr)2/3 = f/2 |
| B. | jH = (St)(Pr)1/3 = f/2 |
| C. | jH = (St)2/3(Pr) = f/2 |
| D. | jH = (St)1/3(Pr) = f/2 |
| Answer» B. jH = (St)(Pr)1/3 = f/2 | |
| 141. |
Peclet number (Pe) is given by____________________? |
| A. | Pe = Re.Pr |
| B. | Pe = Re/Pr |
| C. | Pe = Pr/Re |
| D. | Pe = Nu.Re |
| Answer» B. Pe = Re/Pr | |
| 142. |
_____________ paint has the minimum absorption co-efficient? |
| A. | Black |
| B. | White lead |
| C. | Grey |
| D. | Light cream |
| Answer» C. Grey | |
| 143. |
_______________ paint has the maximum absorption coefficient ? |
| A. | Black |
| B. | Yellow |
| C. | White |
| D. | Grey |
| Answer» B. Yellow | |
| 144. |
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 | |
| 145. |
Overall heat transfer co-efficient of a particular tube is U1. If the same tube with some dirt deposited on either side has coefficient U2, then_________________? |
| A. | U1 = U2 |
| B. | U2 > U1 |
| C. | U1 > U2 |
| D. | U1 = dirt factor – U2 |
| Answer» B. U2 > U1 | |
| 146. |
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°F | |
| 147. |
Out of the following four assumptions used in the derivation of the equation for LMTD [LMTD = (Δt1 – Δt2)/ln(Δt1/Δt2)], which one is subject to the largest deviation in practice ? |
| A. | Constant overall heat transfer co-efficient |
| B. | Constant rate of fluid flow |
| C. | Constant specific heat |
| D. | No partial phase change in the system |
| Answer» C. Constant specific heat | |
| 148. |
Out of 100 kcal/second of incident radiant energy on the surface of a thermally transparent body, 300 kcal/second is reflected back. If the transmissivity of the body is 0.25, the emissivity of the surface will be_________________? |
| A. | 0.35 |
| B. | 0.45 |
| C. | 0.55 |
| D. | 0.85 |
| Answer» C. 0.55 | |
| 149. |
Open pan evaporators are preferred to be used, when the solution to be concentrated is_________________? |
| A. | Scaling |
| B. | Highly viscous |
| C. | Corrosive |
| D. | Salty |
| Answer» C. Corrosive | |
| 150. |
One kilogram of water at 0°C is changed to superheated steam of one atm pressure and 300° C. The major heat consumption in the process will be to________________? |
| A. | Heat the water from 0°C to 100°C |
| B. | Evaporate the water |
| C. | To superheat the steam |
| D. | Data insufficient, can’t be predicted |
| Answer» C. To superheat the steam | |