MCQOPTIONS
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MCQOPTIONS
This section includes 20 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. |
If the pu impedance of a single phase transformer is 0.01+j0.05, then its regulation at p.f. of 0.8 leading will be? |
| A. | 3.8% |
| B. | 2.2% |
| C. | -3.8% |
| D. | -2.2% |
| Answer» E. | |
| 2. |
If the pu impedance of a single phase transformer is 0.01+j0.05, then its regulation at p.f. of 0.8 lagging will be? |
| A. | 3.8% |
| B. | 2.2% |
| C. | -3.8% |
| D. | -2.2% |
| Answer» B. 2.2% | |
| 3. |
A 200/400 V single phase transformer has leakage impedance z= r+jx. Then we can expect zero voltage regulation at power factor of ___________ |
| A. | x/r leading |
| B. | x/r lagging |
| C. | r/x leading |
| D. | r/x lagging |
| Answer» B. x/r lagging | |
| 4. |
With the reference of the diagram below, Choose the most appropriate.A: B: |
| A. | A-lagging pf, B-leading pf |
| B. | B-lagging pf, A-leading pf |
| C. | A-lagging pf, B-lagging pf |
| D. | A-leading pf, B-leading pf |
| Answer» B. B-lagging pf, A-leading pf | |
| 5. |
While estimating voltage regulation of a transformer, keeping ___________ |
| A. | primary voltage constant |
| B. | secondary voltage constant |
| C. | voltage changes constant at primary |
| D. | all of the mentioned |
| Answer» B. secondary voltage constant | |
| 6. |
The voltage regulation for transformer is given by ___________ |
| A. | (E2-V2)/E2 |
| B. | (E2-V2)/V2 |
| C. | (V2-E2)/E2 |
| D. | (V2-E2)/V2 |
| Answer» B. (E2-V2)/V2 | |
| 7. |
If the per unit leakage impedance for the primary of a transformer is ‘x’ on the given rated base value. If the voltage and volt-amperes are halved, then the changed per unit impedance will be ___________ |
| A. | 0.5x |
| B. | 2x |
| C. | 4x |
| D. | x |
| Answer» C. 4x | |
| 8. |
If the per unit leakage impedance for the primary of a transformer is ‘x’ on the given rated base value. If the voltage and volt-amperes are doubled, then the changed per unit impedance will be ___________ |
| A. | 0.5x |
| B. | 2x |
| C. | 4x |
| D. | x |
| Answer» B. 2x | |
| 9. |
While conducting testing on the single phase transformer, one of the student tries to measure the resistance by putting an ammeter across one terminal of primary and other to secondary, the reading obtained will be ___________ |
| A. | infinite |
| B. | zero |
| C. | finite |
| D. | negative finite |
| Answer» B. zero | |
| 10. |
While conducting open circuit test and short circuit test on a transformer, status of low-voltage and high-voltage windings will be such that in ____________ |
| A. | OC test – h.v. open, SC test-l.v. short-circuited |
| B. | OC test – l.v. open, SC test-h.v. short-circuited |
| C. | OC test – l.v. open, SC test-l.v. short-circuited |
| D. | OC test – h.v. open, SC test-h.v. short-circuited |
| Answer» B. OC test – l.v. open, SC test-h.v. short-circuited | |
| 11. |
A 10 kVA, 400/200 V, 1-phase transformer with 2% resistance and 2% leakage reactance. It draws steady short circuit current at which angle? |
| A. | 45° |
| B. | 75° |
| C. | 135° |
| D. | 0° |
| Answer» B. 75° | |
| 12. |
If the pu impedance of a single phase transformer is 0.01+j0.05, then its regulation at p.f. of 0.8 leading will be |
| A. | 3.8% |
| B. | 2.2% |
| C. | -3.8% |
| D. | -2.2% |
| Answer» E. | |
| 13. |
If the pu impedance of a single phase transformer is 0.01+j0.05, then its regulation at p.f. of 0.8 lagging will be |
| A. | 3.8% |
| B. | 2.2% |
| C. | -3.8% |
| D. | -2.2% |
| Answer» B. 2.2% | |
| 14. |
A 200/400 V single phase transformer has leakage impedance z= r+jx. Then we can expect magnitude of load pf of ____ at zero voltage regulation. |
| A. | cosθ = x/z |
| B. | cosθ = r/z |
| C. | cosθ = x/r |
| D. | cosθ = r/x |
| Answer» B. cos‚âà√≠‚Äö√†√® = r/z | |
| 15. |
A 200/400 V single phase transformer has leakage impedance z= r+jx. Then we can expect zero voltage regulation at power factor of |
| A. | x/r leading |
| B. | x/r lagging |
| C. | r/x leading |
| D. | r/x lagging |
| Answer» B. x/r lagging | |
| 16. |
While estimating voltage regulation of a transformer, keeping |
| A. | primary voltage constant |
| B. | secondary voltage constant |
| C. | voltage changes constant at primary |
| D. | all of the mentioned |
| Answer» B. secondary voltage constant | |
| 17. |
The voltage regulation for transformer is given by |
| A. | (E2-V2)/E2 |
| B. | (E2-V2)/V2 |
| C. | (V2-E2)/E2 |
| D. | (V2-E2)/V2 |
| Answer» B. (E2-V2)/V2 | |
| 18. |
If the per unit leakage impedance for the primary of a transformer is ‘x’ on the given rated base value. If the voltage and volt-amperes are doubled, then the changed per unit impedance will be$ |
| A. | 0.5x |
| B. | 2x |
| C. | 4x |
| D. | x |
| Answer» B. 2x | |
| 19. |
While conducting testing on the single phase transformer, one of the student tries to measure the resistance by putting an ammeter across one terminal of primary and other to secondary, the reading obtained will be |
| A. | infinite |
| B. | zero |
| C. | finite |
| D. | negative finite |
| Answer» B. zero | |
| 20. |
While conducting open circuit test and short circuit test on a transformer, status of low-voltage and high-voltage windings will be such that in |
| A. | OC test – h.v. open, SC test-l.v. short-circuited |
| B. | OC test – l.v. open, SC test-h.v. short-circuited |
| C. | OC test – l.v. open, SC test-l.v. short-circuited |
| D. | OC test – h.v. open, SC test-h.v. short-circuited |
| Answer» B. OC test ‚Äö√Ñ√∂‚àö√ë‚àö¬® l.v. open, SC test-h.v. short-circuited | |