| 1. | The transformer oil should have ...... volatility and ...... viscosity. ? | |
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low low
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high high
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low high
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high low
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Report Question| 2. | The nominal short-circuit voltage of the transformer is defined as percentage of ? | |
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the rated primary voltage
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the rated secondary voltage
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the test voltage
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the nominal transformation ratio
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| 3. | Auto-transformer makes effective saving on copper and copper losses, when its transformation ratio is ? | |
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approximately equal to one
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less than one
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great than one
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none of the above
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| 4. | What is the typical use of an autotransformer ? | |
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Control transformer
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Isolating transformer
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Variable transformer
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Toy transformer
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| 5. | A sinusoidal e.m.f. ? | |
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leads the flux inducing it by 180º
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leads the flux inducing it by 90º
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lags the flux inducing it by 180º
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the flux inducing it by 90°
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| 6. | In a transformer the magnitude of mutual flux ? | |
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varies at low loads and constant at high loads
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is low at low loads and high at high loads
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is high at low loads and low at high loads
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same at all loads
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| 7. | The reactance of a transformer depends on ? | |
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leakage flux
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size of the core
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size of the tank
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all of the above
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| 8. | The power transformer is a constant ? | |
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voltage device
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current device
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power device
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main flux device
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| 9. | Which of the following will improve the mutual coupling between primary and secondary circuits ? | |
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High reluctance magnetic core
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Transformer oil of high breakdown voltage
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Low reluctance magnetic core
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Winding material of high resistivity
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| 10. | No-load current of a transformer has ? | |
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has high magnitude and low power factor
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has high magnitude and high power factor
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has small magnitude and high power factor
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has small magnitude and low power factor
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