Heating and Welding Mcqs
This set of Electrical engineering Multiple Choice Questions & Answers (MCQs) focuses on study of “Heating and Welding”. These questions are chosen from a collection of most authoritative and best reference books on Electrical engineering. Our aim is to prepare an individual for competitive exams like NTS, GAT, ECAT, University and College entrance exams, Jobs and interviews. One should practice our MCQS to assimilate Heating and Welding Mcqs comprehensively.
2. It is desirable to operate the arc furnaces at power factor of_____________?
Zero
0.707 lagging
Unity
0.707 leading
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3. Ajax Wyatt furnace is started when____________?
It is filled below core level
It is filled above core level
It is fully empty
None of the above
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4. Radiations from a black body are proportional to____________?
T1
T2
T3
T*
5. Which of the following methods is used to control temperature in resistance furnaces ?
Variation of resistance
Variation of voltage
Periodical switching on and off of the supply
All of the above methods
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6. In arc furnace the function of choke is______________?
To stabilize the arc
To imprpve, power factor
To reduce severity of the surge
None of the above
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7. Hysteresis loss and eddy current loss are used in____________?
Induction heating of steel
Dielectric heating
Induction heating of brass
Resistance heating
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8. In electric press, mica is used because it is _________ conductor of heat but/and __________ conductor of electricity?
Bad, good
Bad, bad
Good, bad
Good, good
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9. In heating the ferromagnetic material by induction heating, heat is produced due to_____________?
Induced current flow through the charge
Hysteresis loss taking place below curie temperature
Due to hysteresis loss as well as eddy current loss takingplace in the charge
None of the above factors
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10. Resistance variation method of temperature control is done by connecting resistance elements in_____________?
Series
Parallel
Series-parallel connections
Star-delta connections
All of the above ways
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11. Which of the following devices is necessarily required for automatic temperature control in a furnace ?
Thermostat
Thermocouple
Auto-transformer
Heating elements of variable resis-tance material
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12. Direct arc furnaces have which of the following power factors ?
Unity
Low, lagging
Low, leading
Any of the above
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13. Which of the following is an advantage of eddy current heating ?
The amount of heat generated can be controlled accurately
Heat at very high rate can be gene-rated
The area of the surface over which heat is produced can be accurately controlled
All of the above
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14. Radiant heating is used for which of the following ?
Annealing of metals
Melting of ferrous metals
Heating of liquids in electric kettle
Drying of paints and varnishes
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15. For radiant heating around 2250°C, the heating elements are made of____________?
Copper alloy
Carbon
Tungsten alloy
Stainless steel alloy
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