Q11. | The electrode of a direct arc furnace is made of | ||||||
A. | tungsten [Wrong Answer] |
B. | graphite [Correct Answer] |
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C. | silver [Wrong Answer] |
D. | copper [Wrong Answer] |
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Q12. | ____ method has leading power factor | ||||||
A. | Resistance heating [Wrong Answer] |
B. | Dielectric heating [Correct Answer] |
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C. | Arc heating [Wrong Answer] |
D. | Induction heating [Wrong Answer] |
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Q13. | Which of the following has the highest value of thermal conductivity ? | ||||||
A. | Water [Wrong Answer] |
B. | Steam [Wrong Answer] |
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C. | Solid ice [Correct Answer] |
D. | Melting ice [Wrong Answer] |
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Q14. | In induction heating ____ is abnormally high. | ||||||
A. | phase angle [Wrong Answer] |
B. | frequency [Correct Answer] |
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C. | current [Wrong Answer] |
D. | voltage [Wrong Answer] |
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Q15. | For intermittent work which of the following furnaces is suitable ? | ||||||
A. | Indirect arc furnace [Correct Answer] |
B. | Core less furnace [Wrong Answer] |
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C. | Either of the above [Wrong Answer] |
D. | None of the above [Wrong Answer] |
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Q16. | In electric press, mica is used because it is ____ conductor of heat but/and ____ conductor of electricity. | ||||||
A. | bad, good [Wrong Answer] |
B. | bad, bad [Wrong Answer] |
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C. | good, bad [Correct Answer] |
D. | good, good [Wrong Answer] |
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Q17. | Direct arc furnaces have which of the following power factors ? | ||||||
A. | Unity [Wrong Answer] |
B. | Low, lagging [Correct Answer] |
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C. | Low, leading [Wrong Answer] |
D. | Any of the above [Wrong Answer] |
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Q18. | ____ is used for heating non-conducting materials. | ||||||
A. | Eddy current heating [Wrong Answer] |
B. | Arc heating [Wrong Answer] |
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C. | Induction heating [Wrong Answer] |
D. | Dielectric heating [Correct Answer] |
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Q19. | Induction heating process is based on which of the following principles ? | ||||||
A. | Thermal ion release principle [Wrong Answer] |
B. | Nucleate heating principle [Wrong Answer] |
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C. | Resistance heating principle [Wrong Answer] |
D. | Electro-magnetic induction principle [Correct Answer] |
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Q20. | By the use of which of the following, high frequency power supply for induction furnaces can be obtained ? | ||||||
A. | Coreless transformers [Wrong Answer] |
B. | Current transformers [Wrong Answer] |
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C. | Motor-generator set [Correct Answer] |
D. | Multi-phase transformer [Wrong Answer] |
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