MCQOPTIONS
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MCQOPTIONS
This section includes 95 Mcqs, each offering curated multiple-choice questions to sharpen your Electrical Engineering knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
Heat is transferred simultaneously by condition, convection and radiation |
| A. | nside boiler furnaces |
| B. | uring melting of ice |
| C. | hrough the surface of the insulted pipe carrying steam |
| D. | rom refrigerator coils to freezer of a refrigerator |
| Answer» B. uring melting of ice | |
| 2. |
A perfect black body is one that |
| A. | ransmits all incident radiations |
| B. | bsorbs all incident radiations |
| C. | eflects all incident radiations |
| D. | bsorbs, reflects and transmits all incident radiations |
| Answer» C. eflects all incident radiations | |
| 3. |
For the transmission of heat from one body to another |
| A. | emperature of the two bodies must be different |
| B. | oth bodies must be solids |
| C. | oth bodies must be in contact |
| D. | t least one of the bodies must have some source of heating |
| Answer» B. oth bodies must be solids | |
| 4. |
Properly of low temperature co-eflficient of heating element is desired due to which of the following reasons? |
| A. | o avoid initial rush of current |
| B. | o avoid change in kW rating with temperature |
| C. | oth (A) and (B) |
| D. | ither (A) or (B) |
| Answer» D. ither (A) or (B) | |
| 5. |
In an electric room heat convector the method of heating used is Resistance heating |
| A. | True |
| B. | False |
| Answer» B. False | |
| 6. |
It is desirable to operate the arc furnaces at power factor of |
| A. | Zero |
| B. | 0.707 lagging |
| C. | Unity |
| D. | 0.707 leading |
| Answer» C. Unity | |
| 7. |
Which of the following methods is used to control temperature in resistance furnaces? |
| A. | Variation of resistance |
| B. | Variation of voltage |
| C. | Periodical switching on and off of the supply |
| D. | All of the above methods |
| Answer» E. | |
| 8. |
By which of the following methods the temperature inside arcane can be varied? |
| A. | By disconnecting some of the heating elements |
| B. | By varying the operating voltage |
| C. | By varying the current through heating elements |
| D. | By any of the above method |
| Answer» E. | |
| 9. |
Which of the following insulating materials was suitable for low temperature applications? |
| A. | Asbestos paper |
| B. | Diatomaceous earth |
| C. | 80 percent magnesia |
| D. | Cork |
| Answer» C. 80 percent magnesia | |
| 10. |
Direct arc furnaces have which of the following power factors? |
| A. | Unity |
| B. | Low, lagging |
| C. | Low, leading |
| D. | Any of the above |
| Answer» C. Low, leading | |
| 11. |
Which of the following devices is necessarily required for automatic temperature control in a furnace? |
| A. | Thermostat |
| B. | Thermocouple |
| C. | Autotransformer |
| D. | Heating elements of variable resistance material |
| Answer» C. Autotransformer | |
| 12. |
________ is used for heating non-conducting materials. |
| A. | Eddy current heating |
| B. | Arc heating |
| C. | Induction heating |
| D. | Dielectric heating |
| Answer» E. | |
| 13. |
Ajax Wyatt furnace is started when |
| A. | It is filled below core level |
| B. | It is filled above core level |
| C. | It is fully empty |
| D. | None of the above |
| Answer» C. It is fully empty | |
| 14. |
The process of heat transfer during the re-entry of satellites and missiles, at very high speeds, into earth?s atmosphere is known as |
| A. | Ablation |
| B. | Radiation |
| C. | Viscous dissipation |
| D. | Irradiation |
| Answer» B. Radiation | |
| 15. |
Method has leading power factor |
| A. | Resistance heating |
| B. | Dielectric heating |
| C. | Arc heating |
| D. | Induction heating |
| Answer» C. Arc heating | |
| 16. |
Hysteresis loss and eddy current loss are used in |
| A. | Induction heating of steel |
| B. | Dielectric heating |
| C. | Induction heating of brass |
| D. | Resistance heating |
| Answer» B. Dielectric heating | |
| 17. |
For radiant heating around 2250°C, the heating elements are made of |
| A. | Copper alloy |
| B. | Carbon |
| C. | Tungsten alloy |
| D. | Stainless steel alloy |
| Answer» D. Stainless steel alloy | |
| 18. |
________ has the highest value of thermal conductivity. |
| A. | Copper |
| B. | Aluminium |
| C. | Brass |
| D. | Steel |
| Answer» B. Aluminium | |
| 19. |
Induction heating takes place it which of the following? |
| A. | Insulating materials |
| B. | Conducting materials which are magnetic |
| C. | Conducting materials which are non-magnetic |
| D. | Conducting materials which may or may not be magnetic |
| Answer» E. | |
| 20. |
Which of the following heating methods has maximum power factor? |
| A. | Arc heating |
| B. | Dielectric heating |
| C. | Induction heating |
| D. | Resistance heating |
| Answer» E. | |
| 21. |
For heating element high resistivity material is chosen to |
| A. | Reduce the length of heating element |
| B. | Increase the life of the heating element |
| C. | Reduce the effect of oxidation |
| D. | Produce large amount of heat |
| Answer» B. Increase the life of the heating element | |
| 22. |
In an electric room heat convector the method of heating used is |
| A. | Arc heating |
| B. | Resistance heating |
| C. | Induction heating |
| D. | Dielectric heating |
| Answer» C. Induction heating | |
| 23. |
In electric press, mica is used because it is _______ conductor of heat but/and________ conductor of electricity. |
| A. | bad, good |
| B. | bad, bad |
| C. | good, bad |
| D. | good, good |
| Answer» D. good, good | |
| 24. |
Induction heating takes place in which of the following? |
| A. | Insulating materials |
| B. | Conducting materials which are magnetic |
| C. | Conducting materials which are nonmagnetic |
| D. | Conducting materials which may or may not be magnetic |
| Answer» E. | |
| 25. |
The temperature inside a furnace is usually measured by which of the following? |
| A. | Optical pyrometer |
| B. | Mercury thermometer |
| C. | Alcohol thermometer |
| D. | Any of the above |
| Answer» B. Mercury thermometer | |
| 26. |
By the use of which of the following, high frequency power supply for induction furnaces can be obtained? |
| A. | Coreless transformers |
| B. | Current transformers |
| C. | Motor-generator set |
| D. | Multiphase transformer |
| Answer» D. Multiphase transformer | |
| 27. |
In a resistance furnace the atmosphere is |
| A. | Oxidizing |
| B. | Deoxidizing |
| C. | Reducing |
| D. | Neutral |
| Answer» B. Deoxidizing | |
| 28. |
In direct arc furnace, which of the following has high value? |
| A. | Current |
| B. | Voltage |
| C. | Power factor |
| D. | All of the above |
| Answer» B. Voltage | |
| 29. |
Due to which of the following reasons it is desirable to have short arc length? |
| A. | To achieve better heating |
| B. | To increase the life of roof refractory |
| C. | To have better stirring action |
| D. | All of the above |
| Answer» E. | |
| 30. |
For intermittent work which of the following furnaces is suitable? |
| A. | Indirect arc furnace |
| B. | Core less furnace |
| C. | Either of the above |
| D. | None of the above |
| Answer» B. Core less furnace | |
| 31. |
Which of the following will happen if the thickness of refractory wall of furnace is increased? |
| A. | Heat loss through furnace wall will increase |
| B. | Temperature inside the furnace will fall |
| C. | Temperature on the outer surface of furnace walls will drop |
| D. | Energy consumption will increase |
| Answer» D. Energy consumption will increase | |
| 32. |
In a domestic cake baking oven the temperature is controlled by |
| A. | Voltage variation |
| B. | Thermostat |
| C. | Autotransformer |
| D. | Series-parallel operation |
| Answer» E. | |
| 33. |
Which of the following is an advantage of heating by electricity? |
| A. | Quicker operation |
| B. | Higher efficiency |
| C. | Absence of flue gases |
| D. | All of the above |
| Answer» E. | |
| 34. |
In induction heating __________ is abnormally high. |
| A. | Phase angle |
| B. | Frequency |
| C. | Current |
| D. | Voltage |
| Answer» C. Current | |
| 35. |
The material of the heating element for a furnace should have |
| A. | Lower melting point |
| B. | Higher temperature coefficient |
| C. | High specific resistance |
| D. | All of the above |
| Answer» D. All of the above | |
| 36. |
In direct arc furnace, which of the following has high value?%! |
| A. | Current |
| B. | Voltage |
| C. | Power factor |
| D. | All of the above |
| Answer» B. Voltage | |
| 37. |
Due to which of the following reasons it is desirable to have short arc length?%! |
| A. | To achieve better heating |
| B. | To increase the life of roof refractory |
| C. | To have better stirring action |
| D. | All of the above |
| Answer» E. | |
| 38. |
For intermittent work which of the following furnaces is suitable?%! |
| A. | Indirect arc furnace |
| B. | Core less furnace |
| C. | Either of the above |
| D. | None of the above |
| Answer» B. Core less furnace | |
| 39. |
In an electric room heat convector the method of heating used is Resistance heating%! |
| A. | True |
| B. | False |
| Answer» B. False | |
| 40. |
It is desirable to operate the arc furnaces at power factor of%! |
| A. | Zero |
| B. | 0.707 lagging |
| C. | Unity |
| D. | 0.707 leading |
| Answer» C. Unity | |
| 41. |
Which of the following methods is used to control temperature in resistance furnaces?%! |
| A. | Variation of resistance |
| B. | Variation of voltage |
| C. | Periodical switching on and off of the supply |
| D. | All of the above methods |
| Answer» E. | |
| 42. |
By which of the following methods the temperature inside arcane can be varied?%! |
| A. | By disconnecting some of the heating elements |
| B. | By varying the operating voltage |
| C. | By varying the current through heating elements |
| D. | By any of the above method |
| Answer» E. | |
| 43. |
Which of the following insulating materials was suitable for low temperature applications?%! |
| A. | Asbestos paper |
| B. | Diatomaceous earth |
| C. | 80 percent magnesia |
| D. | Cork |
| Answer» C. 80 percent magnesia | |
| 44. |
Direct arc furnaces have which of the following power factors?%! |
| A. | Unity |
| B. | Low, lagging |
| C. | Low, leading |
| D. | Any of the above |
| Answer» C. Low, leading | |
| 45. |
In an electric room heat convector the method of heating used is%! |
| A. | Arc heating |
| B. | Resistance heating |
| C. | Induction heating |
| D. | Dielectric heating |
| Answer» C. Induction heating | |
| 46. |
Hysteresis loss and eddy current loss are used in%! |
| A. | Induction heating of steel |
| B. | Dielectric heating |
| C. | Induction heating of brass |
| D. | Resistance heating |
| Answer» B. Dielectric heating | |
| 47. |
Which of the following has the highest value of thermal conductivity?%! |
| A. | Water |
| B. | Steam |
| C. | Solid ice |
| D. | Melting ice |
| Answer» D. Melting ice | |
| 48. |
Ajax Wyatt furnace is started when%! |
| A. | It is filled below core level |
| B. | It is filled above core level |
| C. | It is fully empty |
| D. | None of the above |
| Answer» C. It is fully empty | |
| 49. |
Which of the following heating methods has maximum power factor?%! |
| A. | Arc heating |
| B. | Dielectric heating |
| C. | Induction heating |
| D. | Resistance heating |
| Answer» E. | |
| 50. |
The temperature inside a furnace is usually measured by which of the following?%! |
| A. | Optical pyrometer |
| B. | Mercury thermometer |
| C. | Alcohol thermometer |
| D. | Any of the above |
| Answer» B. Mercury thermometer | |