| 1. | A current is said to be alternating when it changes in ? | |
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magnitude only
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direction only
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both magnitude and direction
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none
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Report Question| 2. | If two sinusoidal of the same frequency but of different amplitudes and phase difference are added, the resultant is a ? | |
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sinusoid of double the original frequency
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sinusoid of the same frequency
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non-sinusoid
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sinusoid of half the original frequency
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| 3. | The reactance offered by a capacitor to ac of frequency 50 Hz is 102. If the frequency is increased to 100 Hz, reactance becomes ? | |
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20?
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40?
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5?
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2.5?
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| 4. | A square wave is fed to an R-C circuit. Then ? | |
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voltage across both R and C is square
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voltage across R is square and across C is not square
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voltage across both R and C is not square
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voltage across C is square and across R is not square
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| 5. | A 240 V single-phase ac source is connected to a load with an impedance of 10 2. A capacitor is connected in parallel with the load. If the capacitor supplies 1,250 VAR, the real power supplied by the source is ? | |
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3,600 W
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2,400 W
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2,880 W
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1,200 W
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| 6. | A source of angular frequency 1 rad/sec has a source impedance consisting of 1 resistance in series with 1 H inductance. The load that will obtain the maximum power transfer is ? | |
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12 resistance in series with 1 F capacitor
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1? resistance
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1? resistance in parallel with 1 H inductance
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12 resistance in parallel with 1 F capacitor
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| 7. | The rated voltage of a 3-phase power system is given as ? | |
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rms phase voltage
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rms line-to-line voltage
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peak line-to-line voltage
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peak phase voltage
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| 8. | For a 3-phase load balanced condition, each phase has the same value of ? | |
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impedance
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resistance
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power factor
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all of these
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| 9. | A 3-phase delta-connected symmetrical load consumes P watts of power from a balanced supply. If the same load is connected in star to the same supply, then what is the power consumption ? | |
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P
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P/3
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3P
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?3P
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| 10. | Two resistors of equal values are connected series across the lines B and C of a symmetrical 3-phase, 400 V system. What is the magnitude of the voltage between the line A and the junction of resistors ? | |
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400//3
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100/3
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200/3
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400/3
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