MCQOPTIONS
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MCQOPTIONS
This section includes 98 Mcqs, each offering curated multiple-choice questions to sharpen your Electrical Engineering Questions knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
Which of the following steps is likely to result in reduction of hysteresis loss in a D.C. generator ? |
| A. | Providing laminations in armature core |
| B. | Providing laminations in stator |
| C. | Using non-magnetic material for frame |
| D. | Using material of low hysteresis co-efficient for armature core material |
| Answer» E. | |
| 2. |
Which of the following test can be performed on DC series motor? |
| A. | Swinburne test |
| B. | Hopkinson test |
| C. | Brake test |
| D. | Field test |
| Answer» E. | |
| 3. |
Which of the following tests will be suitable for testing two similar D.C. series motors of large capacity ? |
| A. | Swinburne’s test |
| B. | Hopkinson’s test |
| C. | Field test |
| D. | Brake test |
| Answer» D. Brake test | |
| 4. |
With the increase in temperature, the speed of DC series motor______________? |
| A. | decreases |
| B. | increases |
| C. | remain same |
| D. | none of the above |
| Answer» B. increases | |
| 5. |
With the increase in temperature, the speed of DC shunt motor____________? |
| A. | decreases |
| B. | increases |
| C. | remain same |
| D. | none of the above |
| Answer» C. remain same | |
| 6. |
Which of the following motor is preferred for operation in highly explosive atmosphere ? |
| A. | Series motor |
| B. | Shunt motor |
| C. | Air motor |
| D. | Battery operated motor |
| Answer» D. Battery operated motor | |
| 7. |
Which of the following method is used for the speed control of DC shunt motor? |
| A. | voltage control method |
| B. | flux control method |
| C. | rheostat control method |
| D. | all of the above |
| Answer» E. | |
| 8. |
Which of the following losses are significantly reduced by laminating the core of a D.C. generator ? |
| A. | Hysteresis losses |
| B. | Eddy current losses |
| C. | Copper losses |
| D. | Windage losses |
| Answer» C. Copper losses | |
| 9. |
Which of the following loss in a D.C. generator varies significantly with the load current ? |
| A. | Field copper loss |
| B. | Windage loss |
| C. | Armature copper loss |
| D. | None of the above |
| Answer» D. None of the above | |
| 10. |
Which of the following law/rule can he used to determine the direction of rotation of D.C. motor ? |
| A. | Lenz’s law |
| B. | Faraday’s law |
| C. | Coloumb’s law |
| D. | Fleming’s left-hand rule |
| Answer» E. | |
| 11. |
Where D.C. motor of H.P. 12 or more requires frequent starting, stopping, reversing and speed control______________? |
| A. | drum type controller is used |
| B. | three point starter is used |
| C. | four point starter is used |
| D. | all above can be used |
| Answer» B. three point starter is used | |
| 12. |
When two D.C. series motors are connected in parallel, the resultant speed is____________? |
| A. | more than the normal speed |
| B. | loss than the normal speed |
| C. | normal speed |
| D. | zero |
| Answer» D. zero | |
| 13. |
When the armature of a D.C. motor rotates, e.m.f. induced is___________? |
| A. | self-induced e.m.f. |
| B. | mutually induced e.m.f. |
| C. | back e.m.f |
| D. | none of the above |
| Answer» D. none of the above | |
| 14. |
Ward Leonard method of speed control is basically a______________? |
| A. | field control method |
| B. | armature controlled method |
| C. | field diverter |
| D. | frequency control method |
| Answer» C. field diverter | |
| 15. |
Ward-Leonard control is basically a____________? |
| A. | voltage control method |
| B. | field divertor method |
| C. | field control method |
| D. | armature resistance control method |
| Answer» B. field divertor method | |
| 16. |
Usually wide and sensitive speed control is desired in case of____________? |
| A. | centrifugal pumps |
| B. | elevators |
| C. | steel rolling mills |
| D. | colliery winders |
| Answer» E. | |
| 17. |
Torque developed by a D.C. motor depends upon_____________? |
| A. | magnetic field |
| B. | active length of the conductor |
| C. | current flow through the conductors |
| D. | number of conductors |
| E. | all above factors |
| Answer» F. | |
| 18. |
To get the speed of D.C, motor below the normal without wastage of electrical energy is used? |
| A. | Ward Leonard control |
| B. | rheostatic control |
| C. | any of the above method |
| D. | none of the above method |
| Answer» B. rheostatic control | |
| 19. |
Three point starter can be used for______________? |
| A. | series motor only |
| B. | shunt motor only |
| C. | compound motor only |
| D. | both shunt and compound motor |
| Answer» E. | |
| 20. |
These days D.C. motors are widely used in____________? |
| A. | pumping sets |
| B. | air compressors |
| C. | electric traction |
| D. | machine shops |
| Answer» D. machine shops | |
| 21. |
The type of D.C. motor used for shears and punches is_____________? |
| A. | shunt motor |
| B. | series motor |
| C. | differential compoutid D.C. motor |
| D. | cumulative compound D.C. motor |
| Answer» E. | |
| 22. |
The total losses in a well designed D.C. generator of 10 kW will be nearly______________? |
| A. | 100 W |
| B. | 500 W |
| C. | 1000 W |
| D. | 1500 W |
| Answer» C. 1000 W | |
| 23. |
The starting resistance of a D.C. motor is generally_______________? |
| A. | low |
| B. | around 500 Q |
| C. | 1000 Q |
| D. | infinitely large |
| Answer» B. around 500 Q | |
| 24. |
The speed of a motor falls from 1100 r.p.m. at no-load to 1050 r.p.m. at rated load. The speed regulation of the motor is______________? |
| A. | 2.36% |
| B. | 4.76% |
| C. | 6.77% |
| D. | 8.84% |
| Answer» C. 6.77% | |
| 25. |
The speed of a D.C. shunt motor more than its full-load speed can be obtained by_____________? |
| A. | decreasing the field current |
| B. | increasing the field current |
| C. | decreasing the armature current |
| D. | increasing the armature current |
| Answer» B. increasing the field current | |
| 26. |
The speed of a D.C. shunt motor is required to be more than full load speed. This is possible by______________? |
| A. | reducing the field current |
| B. | decreasing the armature current |
| C. | increasing the armature current |
| D. | increasing the excitation current |
| E. | none of the above methods |
| Answer» B. decreasing the armature current | |
| 27. |
The speed of a D.C. shunt motor can be increased by_______________? |
| A. | increasing the resistance in armature circuit |
| B. | increasing the resistance in field circuit |
| C. | reducing the resistance in the field circuit |
| D. | reducing the resistance in the armature circuit |
| Answer» C. reducing the resistance in the field circuit | |
| 28. |
The speed of a D.C. series motor is_____________? |
| A. | proportional to the armature current |
| B. | proportional to the square of the armature current |
| C. | proportional to field current |
| D. | inversely proportional to the armature current |
| Answer» E. | |
| 29. |
The size of poxvirus is_______________? |
| A. | 20 nm |
| B. | 200 nm |
| C. | 250 nm |
| D. | 300 nm |
| Answer» E. | |
| 30. |
The ratio of starting torque to full-load torque is least in case of____________? |
| A. | series motors |
| B. | shunt motors |
| C. | compound motors |
| D. | none of the above |
| Answer» C. compound motors | |
| 31. |
The purpose of retardation test on D.C. shunt machines is to find out____________? |
| A. | stray losses |
| B. | eddy current losses |
| C. | field copper losses |
| D. | windage losses |
| Answer» B. eddy current losses | |
| 32. |
The power mentioned on the name plate of an electric motor indicates____________? |
| A. | the power drawn in kW |
| B. | the power drawn in kVA |
| C. | the gross power |
| D. | the output power available at the shaft |
| Answer» E. | |
| 33. |
The plugging gives the____________? |
| A. | zero torque braking |
| B. | smallest torque braking |
| C. | highest torque braking |
| D. | none of the above |
| Answer» D. none of the above | |
| 34. |
The mechanical power developed by a shunt motor will be maximum when the ratio of back e.m.f. to applied voltage is______________? |
| A. | 4.0 |
| B. | 2.0 |
| C. | 1.0 |
| D. | 0.5 |
| Answer» E. | |
| 35. |
The main disadvantage of the Ward-Leonard control method is______________? |
| A. | high initial cost |
| B. | high maintenance cost |
| C. | low efficiency at Hght loads |
| D. | all of the above |
| Answer» E. | |
| 36. |
The losses occurring in a D.C. generator are given below. Which loss is likely to have highest proportion at rated load of the generator ? |
| A. | hysteresis loss |
| B. | field copper loss |
| C. | armature copper loss |
| D. | eddy current loss |
| Answer» D. eddy current loss | |
| 37. |
The hysteresis loss in a D.C. machine least depends on____________? |
| A. | Frequency of magnetic reversals |
| B. | Maximum value of flux density |
| C. | Volume and grade of iron |
| D. | Rate of flow of ventilating air |
| Answer» E. | |
| 38. |
The direction of rotation of a D.C. series motor can be changed by___________? |
| A. | interchanging supply terminals |
| B. | interchanging field terminals |
| C. | either of A. and B. above |
| D. | None of the above |
| Answer» C. either of A. and B. above | |
| 39. |
The current drawn by the armature of D.C. motor is directly proportional to__________? |
| A. | the torque required |
| B. | the speed of the motor |
| C. | the voltage across the terminals |
| D. | none of the above |
| Answer» B. the speed of the motor | |
| 40. |
The condition for maximum efficiency for a D.C. generator is______________? |
| A. | eddy current losses = stray losses |
| B. | hysteresis losses = eddy current losses |
| C. | copper losses = 0 |
| D. | variable losses = constant losses |
| Answer» E. | |
| 41. |
The condition for maximum power in case of D.C. motor is______________? |
| A. | back e.m.f. = 2 x supply voltage |
| B. | back e.m.f. = | x supply voltage |
| C. | supply voltage = | x back e.m.f |
| D. | supply voltage = back e.m.f |
| Answer» C. supply voltage = | x back e.m.f | |
| 42. |
The armature voltage control of D.C. motor provides_____________? |
| A. | constant voltage drive |
| B. | constant current drive |
| C. | constant torque drive |
| D. | none of the above |
| Answer» D. none of the above | |
| 43. |
The armature torque of the D.C. shunt motor is proportional to____________? |
| A. | field flux only |
| B. | armature current only |
| C. | both A. and B. |
| D. | none of the above |
| Answer» C. both A. and B. | |
| 44. |
The armature voltage control of D.C. motor provides____________? |
| A. | constant torque drive |
| B. | constant voltage drive |
| C. | constant current drive |
| D. | none of the above |
| Answer» B. constant voltage drive | |
| 45. |
Regenerative method of braking is based on that___________? |
| A. | back e.m.f. is less than the applied voltage |
| B. | back e.m.f. is equal to the applied voltage |
| C. | back e.m.f. of rotor is more than the applied voltage |
| D. | none of the above |
| Answer» C. back e.m.f. of rotor is more than the applied voltage | |
| 46. |
One D.C. motor drives another D.C. motor. The second D.C. motor when excited and driven_______________? |
| A. | runs as a generator |
| B. | does not run as a generator |
| C. | also runs as a motor comes to stop after sometime |
| Answer» B. does not run as a generator | |
| 47. |
Kingdom Protoctista includes_______________? |
| A. | Prokaryotic organisms |
| B. | Unicellular organisms |
| C. | Fungi |
| D. | Eu-cariotiquic organisms |
| Answer» C. Fungi | |
| 48. |
In which of the following device the generated emf and armature current are in the opposite directions? |
| A. | dc generator |
| B. | dc motor |
| C. | transformer |
| D. | all of the above |
| Answer» C. transformer | |
| 49. |
In Ward-Leonard control the lower limit of speed is imposed by________? |
| A. | residual magnetism of the generator |
| B. | core losses of motor |
| C. | mechanical losses of motor and generator together |
| D. | all of the above |
| Answer» B. core losses of motor | |
| 50. |
In variable speed motor___________? |
| A. | a stronger commutating field is needed at low speed than at high speed |
| B. | a weaker commutating field is needed at low speed than at high speed |
| C. | same commutating field is needed at low speed than at high speed |
| D. | none of the above is correct |
| Answer» C. same commutating field is needed at low speed than at high speed | |