| 1. | Which of the following property is not necessarily desirable in the material for transformer core ? | |
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Mechanical strength
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Low hysteresis loss
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High thermal conductivity
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High permeability
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Report Question| 2. | The highest voltage for transmitting electrical power in India is ? | |
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33 kV
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66 kV
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132 kV
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400 kV
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| 3. | Material used for construction of transformer core is usually ? | |
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wood
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copper
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aluminium
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silicon steel
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| 4. | A transformer cannot raise or lower the voltage of a D.C. supply because ? | |
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there is no need to change the D.C. voltage
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a D.C. circuit. bas more losses
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Faraday's laws of electromagnetic induction are not valid since the rate of change of flux is zero
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none of the above
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| 5. | In a transformer the energy is conveyed from primary to secondary ? | |
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through cooling coil
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through air
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by the flux
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none of the above
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| 6. | A transformer can have zero voltage regulation at ? | |
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leading power factor
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lagging power factor
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unity power factor
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zero power factor
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| 7. | The core used in high frequency transformer is usually ? | |
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copper core
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cost iron core
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air core
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mild steel core
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| 8. | Losses which occur in rotating electric machines and do not occur in transformers are ? | |
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friction and windage losses
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magnetic losses
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hysteresis and eddy current losses
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copper losses
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| 9. | The distribution transformers are designed to keep the iron-losses minimum because ? | |
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the primary of distribution transformer is energised for all the twenty four hours
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iron losses may damage the insulation
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iron-losses will heat up the coil
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none of the above
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| 10. | The iron losses of a transformer can be calculated by knowing the weights of ? | |
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copper winding only
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yokes only
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cores only
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cores and yokes
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