MCQOPTIONS
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MCQOPTIONS
This section includes 10 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. |
In a transformer ______ decreases with increase of the leakage flux. |
| A. | secondary terminal voltage |
| B. | secondary induced voltage |
| C. | primary induced voltage |
| D. | all of the mentioned |
| Answer» B. secondary induced voltage | |
| 2. |
There are two identical transformers A and B such that flux density applied to B is doubled. Then magnetizing current of B is? |
| A. | larger than A |
| B. | double of A |
| C. | half of A |
| D. | same as that of A. |
| Answer» B. double of A | |
| 3. |
If the frequency at the primary supply is varied gradually, then the secondary terminal voltage will __________ |
| A. | not change |
| B. | vary directly |
| C. | will vary oppositely |
| D. | will vary inverse of frequency |
| Answer» B. vary directly | |
| 4. |
The flux involved in the emf equation of a transformer has __________ |
| A. | rms value |
| B. | average value |
| C. | total value |
| D. | maximum value |
| Answer» E. | |
| 5. |
For a single phase transformer operating at normal operating conditions has useful flux of 1 Wb. If the machine is loaded at 0.8 p.f., then its mutual flux __________ |
| A. | may decrease to 0.98 Wb |
| B. | remains constant |
| C. | may increase 1.02 Wb |
| D. | may decrease to 0.8 Wb |
| Answer» B. remains constant | |
| 6. |
If a transformer is fed from a dc 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 | |
| 7. |
A single phase transformer has emf per turn having 2310/220 V, 50Hz transformer as 13 V. The core area is(in square cm)? |
| A. | 393 |
| B. | 277.8 |
| C. | 358.92 |
| D. | 450.03 |
| Answer» B. 277.8 | |
| 8. |
A single phase transformer has emf per turn having 2310/220 V, 50Hz transformer as 13 V. Then the estimated primary turns will be? |
| A. | 189 turns |
| B. | 179 turns |
| C. | 176 turns |
| D. | 190 turns |
| Answer» B. 179 turns | |
| 9. |
CRGO Laminations in a transformer are used to minimize __________ |
| A. | eddy current loss |
| B. | hysteresis loss |
| C. | both eddy current and hysteresis loss |
| D. | ohmic loss |
| Answer» D. ohmic loss | |
| 10. |
In a transformer if the frequency of the supply is varied then the magnetizing current in the core also varies. |
| A. | True |
| B. | False |
| Answer» C. | |