| 1. | Which of the following are the applications of D.C. system ? | |
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Battery charging work
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Arc welding
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Electrolytic and electro-chemical processes
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All of the above
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Report Question| 2. | Which of the following methods may be used to convert AC. system to D.C. ? | |
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Rectifiers
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Motor converters
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Motor-generator sets
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All of the above
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| 3. | In a grid control of mercury arc rectifiers when the grid is made positive relative to cathode, then it the electrons on their may to anode ? | |
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accelerates
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decelerates
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any of the above
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none of the above
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| 4. | Ageing of a selenium rectifier may change the output voltage by ? | |
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5 to 10 per cent
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15 to 20 per cent
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25 to 30 per cent
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none of the above
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| 5. | Which of the following rectifiers are primarily used for charging of low voltage batteries from AC supply ? | |
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Mechanical rectifiers
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Copper oxide rectifiers
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Selenium rectifiers
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Electrolytic rectifiers
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| 6. | The ignited or auxiliary anode in mercury arc rectifier is made of ? | |
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graphite
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boron carbide
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aluminium
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copper
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| 7. | The metal rectifiers, as compared to mercury arc rectifiers ? | |
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operate on low temperatures
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can operate on high voltages
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can operate on heavy loads
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give poor regulation
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| 8. | The applications of selenium rectifiers are usually limited to potential of ? | |
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10 V
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30 V
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60 V
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100 V
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| 9. | Which of the following statement is incorrect ? | |
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Copper oxide rectifier is a linear device
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Copper oxide rectifier is not a perfect rectifier
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Copper oxide rectifier has a low efficiency
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Copper oxide rectifier finds use in control circuits
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| 10. | On which of the following factors the number of phases for which a rectifier should be designed depend ? | |
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The voltage regulation of the rectifier should be low
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ln the output circuit there should be no harmonics
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The power factor of the system should be high
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all of the above
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