MCQOPTIONS
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MCQOPTIONS
This section includes 253 Mcqs, each offering curated multiple-choice questions to sharpen your Heat Transfer (HT) knowledge and support exam preparation. Choose a topic below to get started.
| 101. |
Floating heads are provided in heat exchangers to |
| A. | Facilitate maintenance |
| B. | Regulate the flow |
| C. | Increase the pressure drop |
| D. | Avoid deformation of tubes due to thermal expansion |
| E. | Reduce the pressure drop |
| Answer» E. Reduce the pressure drop | |
| 102. |
Which rays have the least wavelength? |
| A. | Ultraviolet |
| B. | Cosmic rays |
| C. | Irifrared |
| D. | X-rays |
| E. | Radio |
| Answer» C. Irifrared | |
| 103. |
In which case does the thermal conductivity increase from left to right? |
| A. | Aluminium, silver, copper |
| B. | 37,500 kg |
| C. | Aluminium, copper, silver |
| D. | Silver, copper, aluminium |
| E. | Copper, silver, aluminium |
| Answer» D. Silver, copper, aluminium | |
| 104. |
A substance above critical temperature exists as |
| A. | Solid |
| B. | Liquid |
| C. | Wet vapour |
| D. | Gas |
| E. | Dry vapour |
| Answer» E. Dry vapour | |
| 105. |
The process of separation of solutes of different molecular sizes in a liquid solution by use of a sutable membrane is known as |
| A. | Hyper sorption |
| B. | Leaching |
| C. | Adsorption |
| D. | Dialysis |
| E. | Distillation |
| Answer» E. Distillation | |
| 106. |
The rate of heat flow between a solid wall and a fluid (in contact with a solid wall) is given by |
| A. | Wein's Law |
| B. | Kirchhoff's law |
| C. | Newton-Rikhman's Law |
| D. | None of the above |
| E. | Nichrome |
| Answer» D. None of the above | |
| 107. |
In heat exchanger design, one transfer unit means |
| A. | Condition when the change in temperature of 1?C numerically equals the average driving force. |
| B. | The equivalent length of tubes in case the heat exchange was for a temperature difference of 1?C |
| C. | One fluid exchanging with another fluid of the same chemical composition |
| D. | The section of heat exchanger where heat transfer surface area is one square metre |
| E. | The section of heat exchanger which will cause temperature drop of one degree centigrade |
| Answer» B. The equivalent length of tubes in case the heat exchange was for a temperature difference of 1?C | |
| 108. |
In case of ideal mono-atomic gas, the ratio of specific heats would be |
| A. | 1.4 |
| B. | 1.33 |
| C. | 1.41 |
| D. | 1.67 |
| E. | 1 |
| Answer» E. 1 | |
| 109. |
The propose of using multiple pass heat exchangers is to |
| A. | Increase pressure drop |
| B. | Increase the rate of heat transfer |
| C. | Neutralise viscous friction |
| D. | Reduce pressure drop |
| E. | Reduce fluid flow friction losses |
| Answer» C. Neutralise viscous friction | |
| 110. |
The rate of radiant energy, which is emitted by a surface at any temperature and in small wavelength is found from the known rate of energy, which under the same condition would be emitted from a black surface by multiplying with the absorptivity. Above enunciation is known as |
| A. | Planck's law |
| B. | Kirchhoff's law |
| C. | Stefan Boltzman law |
| D. | Lambert rule |
| E. | None of the above |
| Answer» F. | |
| 111. |
Four identical copper cubes are painted with different paints. Now if all the cubes are heated to the same temperature and are left in vacuum, which cube will lose heat more rapidly? The colours of the cubes are |
| A. | Pale blue |
| B. | 37,500 kg |
| C. | Shiny black |
| D. | Dull red |
| E. | shiny white |
| Answer» D. Dull red | |
| 112. |
A device for transferring heat from one fluid to another is known as |
| A. | Lead |
| B. | Heat exchanger |
| C. | Radiation |
| D. | Condenser |
| E. | Evaporator |
| Answer» C. Radiation | |
| 113. |
?40?C is equivalent to |
| A. | ? 40?K |
| B. | 172?R |
| C. | ? 40?F |
| D. | 273?K |
| E. | 500?R |
| Answer» D. 273?K | |
| 114. |
Radio active nuclear waste is treated in |
| A. | Pulsed column extractor |
| B. | Mixer settler extractor |
| C. | Sieve plate extraction column |
| D. | Bollman extractor |
| E. | None of the above |
| Answer» B. Mixer settler extractor | |
| 115. |
The temperature inside a furnace is generally measured by |
| A. | Mercury thermometer |
| B. | Alcohol thermometer |
| C. | Gas thermometer |
| D. | Optical pyrometer |
| E. | Any of the above |
| Answer» E. Any of the above | |
| 116. |
The range of diffusivity of gases in cm2/sec at atmospheric pressure is |
| A. | 10 to 5 |
| B. | More than 10 |
| C. | 5 to 1 |
| D. | Less than 1 |
| E. | 1 |
| Answer» E. 1 | |
| 117. |
Which insulating material is suitable for low temperature applications? |
| A. | 85% magnesia |
| B. | Diatomaceous earth |
| C. | Fused alumina bricks |
| D. | Cork |
| E. | Asbestos paper |
| Answer» C. Fused alumina bricks | |
| 118. |
A 1-2 heat exchanger means |
| A. | Single pass on shell side and double pass on tube side |
| B. | Single pass on tube side and double pass on shell side |
| C. | Two tubes of hot fluid pass through one tube of cold tube |
| D. | Single liquid cools two liwuids at different temperatures |
| E. | Two tubes of cold fluid pass through one tube of hot fluid |
| Answer» B. Single pass on tube side and double pass on shell side | |
| 119. |
Steam traps are used to |
| A. | Heat steam |
| B. | Remove condensate |
| C. | Balance the pressure |
| D. | Regulate the flow |
| E. | Add moisture |
| Answer» C. Balance the pressure | |
| 120. |
At all wavelengths and temperatures the monochromatic emissivity of a white body is equal to |
| A. | Zero |
| B. | Unity |
| C. | 0.1 to 0.5 |
| D. | 0.5 |
| E. | 0.5 to 1 |
| Answer» B. Unity | |
| 121. |
If two systems are being compared on the basis of temperature and heat flux, the similarity being considered is |
| A. | 37,500 kg |
| B. | thermal similarity |
| C. | dynamic similarity |
| D. | geometrical similarity |
| E. | kinematic similarity |
| Answer» C. dynamic similarity | |
| 122. |
If the bubbles formed on a submerged hot surface get absorbed in the mass of liquid, the process of boiling is termed as |
| A. | Nucleate boiling |
| B. | Film boiling |
| C. | Pool boiling |
| D. | Any of the above |
| E. | None of the above |
| Answer» D. Any of the above | |
| 123. |
Thermal conductivity of glass wool depends on |
| A. | Composition |
| B. | Density |
| C. | Porosity |
| D. | Structure |
| E. | All of the above |
| Answer» F. | |
| 124. |
When a body is in thermal equilibrium with its surroundings, the absorptivity and the emissivity of the body are same. This Law is known as |
| A. | Wein's Law |
| B. | Kirchhoff's law |
| C. | Stefan Boltzmann's law |
| D. | None of the above |
| E. | Nichrome |
| Answer» C. Stefan Boltzmann's law | |
| 125. |
Which one of the following approximates to the black body condition? |
| A. | Ice |
| B. | Water |
| C. | Lamp black |
| D. | All of the above |
| E. | None of the above |
| Answer» E. None of the above | |
| 126. |
Baffles are provided in heat exchangers to |
| A. | Provide better mechanical strength |
| B. | Reduce heat transfer rate |
| C. | Reduce vibrations |
| D. | Increase heat transfer rate |
| E. | Remove dirt |
| Answer» E. Remove dirt | |
| 127. |
Heat sensitive liquids are connected |
| A. | By using insulated vessels |
| B. | By using low intensity heating |
| C. | By using deoxidisers |
| D. | By using small quantities |
| E. | By using vacuum |
| Answer» F. | |
| 128. |
The relation between the emissive and absorptive power of a surface is developed under |
| A. | Electrical analogy |
| B. | Stefan-Baltzmann's law |
| C. | Planck's law |
| D. | Kirchhoff's law |
| E. | Law of radiations |
| Answer» E. Law of radiations | |
| 129. |
Two parallel opposed, infinite black planes are maintained at 300?C and 400?C respectively. If the temperature difference is doubled by increasing the temperature from 400?C to 500?C, the heat exchange rate will increase by a factor of about |
| A. | 2.5 |
| B. | 5.5 |
| C. | 8.75 |
| D. | 6.25 |
| E. | 4.5 |
| Answer» B. 5.5 | |
| 130. |
Identity the correct statement |
| A. | Only some substances emit radiation |
| B. | A substance will emit radiation at a particular wavelength only |
| C. | Quality and quantity of radiation depends on the properties of the material only |
| D. | All substances emit radiation the quality and quantity depends on the absolute temperature and the properties of the material composing the radiating body |
| E. | Bodies black in colour are known as black bodies |
| Answer» E. Bodies black in colour are known as black bodies | |
| 131. |
The ratio of thermal conductivity of copper to that of brass is nearly |
| A. | 37,500 kg |
| B. | 8 |
| C. | 4 |
| D. | 2 |
| Answer» E. | |
| 132. |
The overall co-efficients of heat transfer is used in the problems of |
| A. | convection |
| B. | conduction |
| C. | radiation |
| D. | conduction and convection |
| E. | Nichrome |
| Answer» E. Nichrome | |
| 133. |
Which of the following method is used for finding the thermal conductivity of rubber? |
| A. | Lec's disc method |
| B. | Searles method |
| C. | Cylindrical shell method |
| D. | Laby and Hercus method |
| E. | Any of the above |
| Answer» B. Searles method | |
| 134. |
Thermal conductivity of liquids can be determined by |
| A. | Guarded plate method |
| B. | Searles method |
| C. | Laby and Hercus method |
| D. | Any of the above |
| E. | None of the above |
| Answer» B. Searles method | |
| 135. |
Which of the following material has thermal conductivity closest to silver? |
| A. | Steel |
| B. | 37,500 kg |
| C. | Aluminium |
| D. | Brass |
| E. | Copper |
| Answer» F. | |
| 136. |
What energy transformation takes place when ice and salt mixture is converted into water |
| A. | Heat energy to sensible heat |
| B. | Kinetic energy to heat energy |
| C. | Heat energy to latent heat |
| D. | Heat energy to potential energy |
| E. | Heat energy to kinetic energy |
| Answer» D. Heat energy to potential energy | |
| 137. |
In air prelieater for boiler heat is least transferred by |
| A. | Convection |
| B. | Conduction, convection and radiation. |
| C. | Conduction and convection |
| D. | Conduction |
| E. | Radiation |
| Answer» F. | |
| 138. |
Which sample of concrete may be expected to have highest value of thermal conductivity |
| A. | Dry concrete having 0.4% rein-forcement |
| B. | Concrete having 10% moisture by volume |
| C. | Concrete having 10% meisture by volume and 0.4% reinforcement |
| D. | Dry concrete |
| E. | Concrete having 10% moisture by volume and 0.6% reinforcement |
| Answer» F. | |
| 139. |
Non-isotropic conductivity is exhibited in case of |
| A. | Steel |
| B. | Wood |
| C. | Copper |
| D. | Lead |
| E. | Brass |
| Answer» C. Copper | |
| 140. |
The rate of energy stored in the wall will be |
| A. | 50 kcal/sec |
| B. | 50 kcal/min |
| C. | 200 kcal/min |
| D. | 50 kcal/hr |
| E. | 200 kcal/hr |
| Answer» D. 50 kcal/hr | |
| 141. |
Any of the following could be the unit for Stefan Boltzmann constant EXCEPT |
| A. | cal / cm2-sec-k4 |
| B. | BTU/ft2-hr-R4 |
| C. | W / m2k4 |
| D. | 37,500 kg |
| E. | erg / cm-k4 |
| Answer» F. | |
| 142. |
A relationship between the temperature of a black body and the wavelength at which the maximum value of monochromatic emission power occurs, is established under |
| A. | D' lambert's rule |
| B. | Stefan-Bolzmann's law |
| C. | Planck's law |
| D. | Wein's displacement law |
| E. | Kirchhoff's law |
| Answer» E. Kirchhoff's law | |
| 143. |
Pyrometer which react to all wavelengths of incident radiant energy are known as |
| A. | Multicolour pyrometers |
| B. | Total radiation pyrometers |
| C. | Polarising pyrometers |
| D. | Optical pyrometers |
| E. | Ddisappearing filament type pyrometers |
| Answer» C. Polarising pyrometers | |
| 144. |
In case of white body, absorptivity is |
| A. | Between 0 to 0.5 |
| B. | 1 |
| C. | Zero |
| D. | More than 0.5 |
| E. | 37,500 kg |
| Answer» D. More than 0.5 | |
| 145. |
A constant gas thermometer is based on |
| A. | Avogadro's law |
| B. | Graham's law |
| C. | Charle's law |
| D. | Boyle's law |
| E. | 37,500 kg |
| Answer» D. Boyle's law | |
| 146. |
Steady state heat transfer occurs when |
| A. | The flow of heat is uniform |
| B. | The flow of heat is uniformly increasing |
| C. | The flow of heat is uniformly decreasing |
| D. | The flow of heat is negligible |
| E. | The flow of heat is independent of time |
| Answer» D. The flow of heat is negligible | |
| 147. |
Heat is shown to be closely related to |
| A. | Energy |
| B. | Momentum |
| C. | Temperature |
| D. | Waveform |
| E. | A fluid |
| Answer» D. Waveform | |
| 148. |
There metal walls of same cross-sectional area having thermal conductivity in the ratio 1 : 2 : 4 transfer heat at the rate of 15000 kcal/hr. For same thickness of wall, the temperature deop will be in the ratio |
| A. | 1 ; 2 ; 4 |
| B. | 1 : |
| C. | 4 ; 2 ; 1 |
| D. | 1 ; 1 ; 1 |
| Answer» C. 4 ; 2 ; 1 | |
| 149. |
The rate of heat loss through a furnace wall is 1000 kcal per hour when inside temperature is 1000?C and outside wall temperature is 500?C. What should be the wall thickness in case the thermal conductivity of wall material is 0.5 kcal/m-hr?C |
| A. | 25 cm |
| B. | 12.5 cm |
| C. | 50 cm |
| D. | 60 cm |
| E. | 40 cm |
| Answer» B. 12.5 cm | |
| 150. |
Thermal conductivity of air at room temperature in kcal/m-hr-?C is nearly |
| A. | 0.1 |
| B. | 0.001 |
| C. | 0.005 |
| D. | 0.05 |
| E. | 0.01 |
| Answer» B. 0.001 | |