MCQOPTIONS
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MCQOPTIONS
This section includes 15 Mcqs, each offering curated multiple-choice questions to sharpen your Electrical Engineering (MCQ) questions and answers knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
A 120 V shunt generator running at 850 rpm has its armature and shunt field resistance of 0.15 ohm and 50 ohm respectively. It supplies 200 lamps each rated at 60 W, 100 V. The friction and windageand core loss of the machine is 400 W. its armature copper loss on full load and shunt field loss is |
| A. | 2156.7 W, 200 W |
| B. | 2232.6 W, 200 W |
| C. | 2156.7 W, 240 W |
| D. | 2232.6 W, 240 W |
| Answer» C. 2156.7 W, 240 W | |
| 2. |
In sumpner s test, the net voltage in the local circuit of secondary s is |
| A. | Equal to zero |
| B. | Twice of the induced emf in each secondary s |
| C. | Equal to the induced emf in each secondary s |
| D. | Square of the induced emf in each secondary s |
| Answer» B. Twice of the induced emf in each secondary s | |
| 3. |
If W1 is the input power measured by the wattmeter connected across the primaries and W2 is the measurement of wattmeter connected in secondary s while performing sumpner s test then iron losses and copper losses is equal to |
| A. | W1, W2 |
| B. | W1 / 2, 2 * W2 |
| C. | 2 * W1, W2 / 2 |
| D. | W1 / 2, W2 / 2 |
| Answer» E. | |
| 4. |
While conducting the sumpner s test, the primaries of the two identical transformers are connected in parallel across the supply. The secondary s are connected in |
| A. | Parallel |
| B. | Series opposition |
| C. | Both in series and parallel |
| D. | Not connected at all |
| Answer» C. Both in series and parallel | |
| 5. |
While performing sumpner s test on transformer, if the secondary are not in series opposition then the meter will read |
| A. | 0 |
| B. | Twice of the induced emf in each secondary s |
| C. | Equal to the induced emf in each secondary s |
| D. | Keep fluctuating |
| Answer» C. Equal to the induced emf in each secondary s | |
| 6. |
Split phase induction motors are available in the range of |
| A. | 1/2 to 1/10 kW |
| B. | 1/20 to 1/2 kW |
| C. | 1/10 to 1/20 kW |
| D. | None of these |
| Answer» C. 1/10 to 1/20 kW | |
| 7. |
For a two winding transformer if VA rating is given by (VA) and K is the transformation ratio of an autotransformer then the VA rating of the autotransformer is given by |
| A. | (K/(K-1)) * (VA) |
| B. | (K/(1-K)) * (VA) |
| C. | ((1-K)/K) * (VA) |
| D. | ((K-1)/K) * (VA) |
| Answer» B. (K/(1-K)) * (VA) | |
| 8. |
If a two winding transformer is converted into an autotransformerby applying additive polarity and subtractive polarity which results in the secondary voltages of 1840 and 1810 volts. Then the primary and secondary voltages of transformer are |
| A. | 1800V, 50V |
| B. | 1810V, 40V |
| C. | 1820V, 30V |
| D. | 1825V, 15V |
| Answer» E. | |
| 9. |
Small iron core transformers used in certain frequency range is also called audio frequency transformer. The audio frequency range is |
| A. | 20 t0 2000 Hz |
| B. | 20 to 20000 Hz |
| C. | 2 to 2000 Hz |
| D. | 200 to 20000 Hz |
| Answer» C. 2 to 2000 Hz | |
| 10. |
A ferro reso t transformer regulation is also known as |
| A. | Constant current transformer |
| B. | Constant voltage transformer |
| C. | Variable current transformer |
| D. | Variable voltage transformer |
| Answer» B. Constant voltage transformer | |
| 11. |
With a bank of two single phase transformers connected in V - V fashion supplying a balanced three phase load with Cos as power factor. The power factor of the two transformers is given by |
| A. | Cos , Cos |
| B. | Cos , Cos(30+ ) |
| C. | Cos(30- ), Cos(30+ ) |
| D. | Cos(30- ), Cos |
| Answer» D. Cos(30- ), Cos | |
| 12. |
The given figure shows the load characteristics of an alternator. Which among the following is correct? |
| A. | A Leading p.f., B unity p.f., C lagging p.f. |
| B. | A Lagging p.f., B unity p.f., C leading p.f. |
| C. | A Leading p.f., B lagging p.f., C unity p.f. |
| D. | A Unity p.f., B leading p.f., C lagging p.f. |
| Answer» B. A Lagging p.f., B unity p.f., C leading p.f. | |
| 13. |
The average emf induced per turn in a transformer is given by |
| A. | 1.11f |
| B. | 0.5f |
| C. | 4f |
| D. | 8f |
| Answer» D. 8f | |
| 14. |
In transformers for maximum voltage regulation to occur, the power factor and magnitude is |
| A. | Lagging, Z |
| B. | Leading, Z |
| C. | Unity, Z |
| D. | None of these |
| Answer» B. Leading, Z | |
| 15. |
A transformer when connected to a 230V, 50Hz supply,under no loaddraws a current of 4A at a power factor of 0.2 lagging. The magnetizing current and core loss is equal to |
| A. | 3.919A, 184W |
| B. | 1.84A, 391.9W |
| C. | 39.19A, 184W |
| D. | 3A, 180W |
| Answer» B. 1.84A, 391.9W | |