| 1. | What will be the reflection co-efficient of the wave of load connected to transmission line if surge impedance of the line is equal to load ? | |
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Infinity
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Zero
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Unity
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None of the above
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View Answer
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Report Question| 2. | To reduce short circuit fault currents .......... are used ? | |
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capacitors
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reactors
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resistors
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none of the above
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| 3. | Ungrounded neutral transmission system is not recommended because of system ? | |
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being inadequately protected against ground fault
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insulation overstress may lead to failure and subsequent phase to phase faults
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insulation being overstressed due to over voltages
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all of the above
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| 4. | The ground wire should not be smaller than No ....... copper ? | |
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4
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2
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6
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10
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| 5. | The arc voltage produced in A.C. circuit breaker is always ? | |
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leading the arc current by 90º
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in phase with the arc current
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none of the above
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lagging the arc current by 90º
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| 6. | Protective relays are devices that detect abnormal conditions in electrical circuits by measuring ? | |
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voltage during abnormal condition
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constantly the electrical quantities which differ during normal and abnormal conditions
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current during abnormal condition
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none of the above
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| 7. | A differential relay measures the vector difference between ? | |
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two or more similar electrical quantities
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two voltages
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currents
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none of the above
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| 8. | The advantage of neutral earthing is ? | |
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freedom from persistent arcing grounds
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over voltages due to lightning can be discharged to earth
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simplified design earth fault protection
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all of the above
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| 9. | In circuit breakers, the advantage of using oil as quenching medium is ? | |
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absorption of arc energy
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oil has high dielectric strength
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oil acts as insulator
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all of the above
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| 10. | Which of the following is used in liquid fuses ? | |
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Carbon tetrachloride
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Transformer oil
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Sulphur hexafluoride
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Distilled water
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