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.
| 1. |
Two bodies one hot and the other cold are kept in vacuum. What will happen to the temperature of the hot body after sometime? |
| A. | Increases due to convection |
| B. | Remains the same |
| C. | Decreases due to convection |
| D. | Increases due to radiation |
| E. | Decreases due to radiation |
| Answer» F. | |
| 2. |
If a body reflects entire radiation incident on it, then it is known as |
| A. | White body |
| B. | Black body |
| C. | Grey body |
| D. | Transparent body |
| E. | Opaque body |
| Answer» B. Black body | |
| 3. |
In a psychrometric chart the abscissa represents |
| A. | Specific humidity |
| B. | Relative humidity |
| C. | Enthalpy |
| D. | Dry bulb temperature |
| E. | Wet bulb temperature |
| Answer» E. Wet bulb temperature | |
| 4. |
The highest value of thermal conductivity is expected for |
| A. | Solid ice |
| B. | Water |
| C. | Melting ice |
| D. | Steam |
| E. | Boiling water |
| Answer» B. Water | |
| 5. |
Elongation of a rod when heated |
| A. | Is proportional to original length |
| B. | Is proportional to length |
| C. | Is inversely proportional to linear strain |
| D. | Is inversely proportional to original length |
| E. | Does not depend on its length |
| Answer» B. Is proportional to length | |
| 6. |
Ablation heat transfer method is used on |
| A. | nuclear war heads |
| B. | submarines |
| C. | 37,500 kg |
| D. | satellites |
| E. | rockets |
| Answer» E. rockets | |
| 7. |
Plank's law of radiation is applicable to |
| A. | Radiation of any kind |
| B. | Temperature radiation |
| C. | Monochromatic radiation |
| D. | Thermal radiation |
| E. | None of the above |
| Answer» D. Thermal radiation | |
| 8. |
If the amount of radiant energy received per unit area per second from the sun is measured at the Earth, Mars and Jupiter it will be |
| A. | in the decreasing order - Jupiter, Mars, Earth |
| B. | in the increasing order - Jupiter, Mars, Earth |
| C. | identical on all the three planets |
| D. | 37,500 kg |
| E. | in the increasing order - Earth, Mars, Jupiter |
| Answer» C. identical on all the three planets | |
| 9. |
The phenomenon of boiling the milk in an open container when milk spills over the vessel is termed as |
| A. | Film boiling |
| B. | Pool boiling |
| C. | Sub-cooled boiling |
| D. | Interface evaporation |
| E. | Nuclear boiling |
| Answer» B. Pool boiling | |
| 10. |
The surface temperatures of a flat wall are 650?C and 450?C respectively and the thermal conductivity of the wall material is 0.30 kcal/m-hr-?C. The heat flux for a wall of 20 cm thickness will be |
| A. | 60 kcal/m2-hr |
| B. | 600 kcal/m2-hr |
| C. | 120 kcal/m2-hr |
| D. | 300 kcal/m2-hr |
| E. | 450 kcal/m2-hr |
| Answer» E. 450 kcal/m2-hr | |
| 11. |
Transient heat flow occurs in |
| A. | Cooling of casting |
| B. | Heating and cooling of buildings due to sun |
| C. | Electric conductors carrying current |
| D. | Melting of ice |
| E. | Insulated pipes carrying superheated steam |
| Answer» C. Electric conductors carrying current | |
| 12. |
Transformer oil having kinematic viscosity of 3.66 x 10-6 m2/s flows through a tube 8 mm diameter at velocity of 0.6 m/s. The value of Reynolds number of flow would be |
| A. | 1510 |
| B. | 1625 |
| C. | 1000 |
| D. | 1310 |
| E. | 1415 |
| Answer» E. 1415 | |
| 13. |
The thermal conductivity of wood depends upon |
| A. | Density |
| B. | Moisture content |
| C. | Temperature |
| D. | All of the above |
| E. | None of the above |
| Answer» E. None of the above | |
| 14. |
In case of natural covection, the Nusselt number is function of |
| A. | Reynolds number |
| B. | Reynolds number and Prandtl number |
| C. | Grashof's number and Prandtl number |
| D. | Weber number and Mach number |
| E. | None of the above |
| Answer» D. Weber number and Mach number | |
| 15. |
A hollow sphere with uniform interior temperature and a small hole behaves very nearly as a |
| A. | White body |
| B. | Transparent body |
| C. | Opaque body |
| D. | Black body |
| E. | Grey body |
| Answer» E. Grey body | |
| 16. |
Which of the following is a minimum boiling azeotrope? |
| A. | Acetone-chloroform |
| B. | Molasses-water |
| C. | Benzene-toluene |
| D. | Iso-butanol-water |
| E. | Carbon disulphide-acetone |
| Answer» F. | |
| 17. |
A perfect black body is the one which |
| A. | Absorbs all incident radiation |
| B. | Reflects all incident radiation |
| C. | Absorbs most of the incident radiation |
| D. | Is coated with lamp black |
| E. | None of the above |
| Answer» B. Reflects all incident radiation | |
| 18. |
When analogy is drawn between heat flow and electricity flow in circuits, the heat flow of thermal circuits is equated in the electrical circuit against |
| A. | Charge (coulombs) |
| B. | Resistance |
| C. | 1 ; 81 |
| D. | Current |
| E. | Voltage |
| Answer» E. Voltage | |
| 19. |
In case of a body transparent to thermal radiation |
| A. | transmissibility = 0 |
| B. | 37,500 kg |
| C. | absorptivity = 1 |
| D. | reflectivity = 1 |
| E. | absorptivity = reflectivity = 0 |
| Answer» F. | |
| 20. |
Three rods one made of glass, one of pure aluminium and one made of wrought iron are heated to 150?C. All the rods are 15 mm in diameter and 300 mm long. The lowest temperature at the free end of the rods will occur in case of |
| A. | Glass rod |
| B. | Wrought iron rod |
| C. | Temperature will depend on the surrounding air temperature |
| D. | Aluminium rod |
| E. | Temperature will be same for all the three rods at free end |
| Answer» B. Wrought iron rod | |
| 21. |
The heat of sum reaches to us according to |
| A. | radiation |
| B. | conduction |
| C. | convection |
| D. | None of the above |
| E. | Nichrome |
| Answer» B. conduction | |
| 22. |
A dimensionless group which represents the rate of the (product of intertial forces times buoyant forces) to viscous force squared is known as |
| A. | Reynolds number |
| B. | Mach number |
| C. | Prandtl number |
| D. | Grashof number |
| E. | Nusselt number |
| Answer» E. Nusselt number | |
| 23. |
Body A is kept in contact with body B. Heat will flow from A to B, if |
| A. | The heat content of A is greater than that of B |
| B. | The temperature of A is greter than that of B |
| C. | The specific heat of A is greater than that of B |
| D. | The specific heat of A is lower than that of B |
| E. | None of the above |
| Answer» C. The specific heat of A is greater than that of B | |
| 24. |
Which of the following have the same units? |
| A. | Stefan's canstant and Boltzmann constant |
| B. | Plank's constant and Stefan's constant |
| C. | Planck's constant and angular momentum |
| D. | Boltzmann constant and Planck's constant |
| E. | 37,500 kg |
| Answer» D. Boltzmann constant and Planck's constant | |
| 25. |
All heat transfer processes |
| A. | Obey Newton's law |
| B. | Involve temperature difference between the bodies |
| C. | Obey first law of thermodynamics |
| D. | Obey second law of thermodynamics |
| E. | Involve transfer of energy |
| Answer» C. Obey first law of thermodynamics | |
| 26. |
Absolute zero is |
| A. | 0?C |
| B. | 0?R |
| C. | 0?F |
| D. | 0?K |
| E. | 273?C |
| Answer» B. 0?R | |
| 27. |
A liquid is boiling in a a air tight vessel. Using an exhaust tube, the vapour is pumped out at a faster rate. What happens to the liquid? |
| A. | Temperature goes down, doiling continues |
| B. | Temperature goes down, boiling stops |
| C. | Temperature goes up, boiling continues |
| D. | Nothing changes |
| E. | Temperature goes up, boiling stops |
| Answer» B. Temperature goes down, boiling stops | |
| 28. |
A liquid to liquid counterflow heat exchanger is used to heat cold fluid from 50?C to 150?C. Assuming that the hot fluid enters at 250?C and leaves at 200?C, the log mean temperature difference for the heat exchanger will be closer to |
| A. | 137?C |
| B. | 37,500 kg |
| C. | 128?C |
| D. | 133?C |
| E. | 100?C |
| Answer» D. 133?C | |
| 29. |
Thermal conductivity of air at room temperature is approximately |
| A. | 0.02 kcal/m-hr-?C |
| B. | 0.002 kcal/m-hr-?C |
| C. | 20.0 kcal/m-hr-?C |
| D. | 0.2 kcal/m-hr-?C |
| E. | 2.0 kcal/m-hr-?C |
| Answer» B. 0.002 kcal/m-hr-?C | |
| 30. |
The ratio of the actual vapour pressure to the pressure of saturated vapour at the prevailing dry bulb temperature is known as |
| A. | Humidity |
| B. | Relative humidity |
| C. | Specific humidity |
| D. | Humidity ratio |
| E. | Vapour humidity |
| Answer» C. Specific humidity | |
| 31. |
A prototype is |
| A. | a dynamically similar model on reduced scale |
| B. | a kinematically similar model on reduced scale |
| C. | 37,500 kg |
| D. | a geometrical similar model on reduced scale |
| E. | a full size structure employed in actual engineering design |
| Answer» F. | |
| 32. |
In case of solids, the heat transfer takes place according to |
| A. | radiation |
| B. | conduction |
| C. | convection |
| D. | Both (A) and (C) |
| E. | Nichrome |
| Answer» C. convection | |
| 33. |
The ratio of heat transfer coefficient to the flow of heat per unit temperature rise due to the velocity of the fluid is known as |
| A. | Stanton number |
| B. | Weber number |
| C. | Prandtl number |
| D. | 37,500 kg |
| E. | Grashoff number |
| Answer» B. Weber number | |
| 34. |
The first stage of crystal formation is |
| A. | Nucleation |
| B. | Separation |
| C. | Foaming |
| D. | Vortexing |
| E. | None of the above |
| Answer» B. Separation | |
| 35. |
The equation E = ? AT4 represents |
| A. | Wein's Law |
| B. | Kirchhoff's law |
| C. | Stefan Boltzmann's law |
| D. | None of the above |
| E. | Nichrome |
| Answer» D. None of the above | |
| 36. |
The surface which diffusely reflects and emits the same amount of energy which it receives by radiation is known as |
| A. | A perfect black surface |
| B. | A perfect grey surface |
| C. | A perfect white surface |
| D. | A perfect radiating surface |
| E. | None of the above |
| Answer» E. None of the above | |
| 37. |
Which evaporator is preferred for concentrating the fruit juice? |
| A. | Agitated film evaporator |
| B. | Falling film evaporator |
| C. | Long vertical tube evaporator |
| D. | Zig-zag film evaporator |
| E. | Short vertical tube evaporator |
| Answer» C. Long vertical tube evaporator | |
| 38. |
What energy transformation takes place when ice is converted into water |
| A. | Heat energy to kinetic energy |
| B. | Kinetic energy to heat energy |
| C. | Heat energy to latent heat |
| D. | Heat energy to potential energy |
| E. | None of the above |
| Answer» D. Heat energy to potential energy | |
| 39. |
Two pieces of wood are placed in sunlight. One is painted white and the other is painted black. It can be concluded that |
| A. | White painted wood will not absorb any solar radiation |
| B. | Black painted wood will not absorb any solar radiation |
| C. | Black painted wood will absorb less heat as compared to white painted wood |
| D. | 37,500 kg |
| E. | Black painted wood will absorb more hcat as compared to white painted wood |
| Answer» F. | |
| 40. |
Non-dimensional number generally involved in case of heat transfer from horizontal cylinder by natural convection is |
| A. | Reynolds number |
| B. | Nusselt number |
| C. | Prandtl number |
| D. | Grashof's numbr |
| E. | (B), (C) and (D) above |
| Answer» F. | |
| 41. |
A Foreman of an automobile workshop wants to measure the temperature inside the piston of a car, whose temperature will be of the order of 700?C (accurate upto 1?C). The best thermometer to use is |
| A. | Constant volume hydrogen thermometer |
| B. | Thermo electric thermometer |
| C. | Platinum resistance thermometer |
| D. | Optical pyrometer |
| E. | Constant volume nitrogen thermometer |
| Answer» C. Platinum resistance thermometer | |
| 42. |
Prandtl number for gases is |
| A. | more than 1000 |
| B. | 37,500 kg |
| C. | near unity |
| D. | between 100 and 1000 |
| E. | between 10 to 100 |
| Answer» D. between 100 and 1000 | |
| 43. |
A dimensionless number representing the ratio of inertia forces to viscous forces is known as |
| A. | Mach number |
| B. | Prandtl number |
| C. | Reynolds number |
| D. | Nusselt number |
| E. | Stanton number |
| Answer» D. Nusselt number | |
| 44. |
Which of the following can be used to measure a temperature around -50?C? |
| A. | Platinum resistance thermometer |
| B. | Thermocouple |
| C. | Alcohol thermometer |
| D. | Mercury thermometer |
| E. | 37,500 kg |
| Answer» D. Mercury thermometer | |
| 45. |
What whould be shape of an ideal thermometer? |
| A. | Spherical |
| B. | Cylindrical |
| C. | Cubical |
| D. | Rectangular |
| E. | None of the above |
| Answer» B. Cylindrical | |
| 46. |
Molecular transmission of heat is smallest in case of |
| A. | Alloys |
| B. | Solids |
| C. | Liquids with impurities |
| D. | Gases |
| E. | Liquids |
| Answer» E. Liquids | |
| 47. |
Insulation in cavity walls is |
| A. | Water |
| B. | Air |
| C. | Cork |
| D. | Wood |
| E. | None of the above |
| Answer» C. Cork | |
| 48. |
The net radiant interchange per square metre for two large parallel planes at temperatures of 1000?K and 100?K respectively, would be roughly |
| A. | 240 kcal/hr |
| B. | 75 kcal/hr |
| C. | 25 kcal/hr |
| D. | 480 kcal/hr |
| E. | 120 kcal/hr |
| Answer» D. 480 kcal/hr | |
| 49. |
Which method can be used for heating wood? |
| A. | Flame heating |
| B. | Resistance heating |
| C. | Dielectric heating |
| D. | Radiation heating |
| E. | Any of the above |
| Answer» D. Radiation heating | |
| 50. |
Which dimensionless number correlates the relative thickness of the hydrodynamic and thermal boundary layers? |
| A. | Mach number |
| B. | 37,500 kg |
| C. | Prandlt number |
| D. | Nusselt number |
| E. | Crash off number |
| Answer» D. Nusselt number | |