MCQOPTIONS
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MCQOPTIONS
This section includes 14 Mcqs, each offering curated multiple-choice questions to sharpen your Electrical Machines knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
Energising the transformer primary from a triangular wave flux makes the output voltage as __________ |
| A. | square wave shifted by 90 |
| B. | a sine wave |
| C. | a triangular wave |
| D. | a square wave |
| Answer» E. | |
| 2. |
A 400/200V transformer has total resistance of 0.04 p.u on its L.V side. This resistance when referred to H.V side would be? |
| A. | 0.04 |
| B. | 0.02 |
| C. | 0.01 |
| D. | 0.08 |
| Answer» B. 0.02 | |
| 3. |
In a single phase transformer,the no-load current lags the applied voltage by __________ |
| A. | 90 |
| B. | about 75 |
| C. | 0 |
| D. | about 110 |
| Answer» C. 0 | |
| 4. |
Energizing the transformer primary from a triangular wave voltage source makes the output voltage as __________ |
| A. | zero |
| B. | a sine wave |
| C. | a triangular wave |
| D. | a pulsed wave |
| Answer» D. a pulsed wave | |
| 5. |
In case of a power transformer, the no load current in terms of rated correct is? |
| A. | 10-20% |
| B. | 2-6% |
| C. | 15-20% |
| D. | 30-50% |
| Answer» C. 15-20% | |
| 6. |
We laminate transformer core to reduce ___________ |
| A. | eddy current loss |
| B. | hysteresis loss |
| C. | both eddy current and hysteresis loss |
| D. | ohmic loss |
| Answer» B. hysteresis loss | |
| 7. |
In an oil filled transformer, the application of oil is for ___________ |
| A. | cooling |
| B. | insulation |
| C. | both cooling and insulation |
| D. | preventing the accumulation of dust |
| Answer» D. preventing the accumulation of dust | |
| 8. |
Considering a transformer at no load is excited at rated voltage. A small recognizable gap is made in the yoke of the limbs. With this altercation, the transformer core flux ___________ |
| A. | will decrease and magnetizing current will increase |
| B. | will remain constant and magnetizing current will increase |
| C. | as well as magnetizing current will increase |
| D. | as well as magnetizing current both will decrease |
| Answer» C. as well as magnetizing current will increase | |
| 9. |
A transformer has sometimes more than two ratings depending upon the use of ___________ |
| A. | the cooling application |
| B. | type of windings |
| C. | type of core |
| D. | type of insulation to be given |
| Answer» B. type of windings | |
| 10. |
In an ideal transformer, the impedance can be transformed from one side to the other ___________ |
| A. | in direct proportion to square of turns-ratio |
| B. | in direct proportion to turns-ratio |
| C. | in inverse proportion to square turns-ratio |
| D. | in inverse proportion to turns-ratio |
| Answer» B. in direct proportion to turns-ratio | |
| 11. |
If a transformer is fed from a 220V and dc supply rather than a 1-phase ac supply, then the transformer will ___________ |
| A. | burn its windings |
| B. | operate normal |
| C. | will not operate |
| D. | will give very small leakage flux |
| Answer» B. operate normal | |
| 12. |
Transformer action requires a ___________ |
| A. | constant magnetic flux |
| B. | increasing magnetic flux |
| C. | alternating magnetic flux |
| D. | alternating electric flux |
| Answer» D. alternating electric flux | |
| 13. |
The non linear magnetization curve of a practical transformer will introduce _____________ |
| A. | heating |
| B. | higher order harmonics |
| C. | magnetostriction |
| D. | all of the mentioned |
| Answer» E. | |
| 14. |
The output voltage seen at the CRO connected at the secondary terminals is square wave. Then the flux density used for energizing the primary is? |
| A. | triangular |
| B. | sinusoidal |
| C. | saw tooth wave |
| D. | square wave |
| Answer» B. sinusoidal | |