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. |
THE_ELECTROMAGNETIC_TORQUE_DEVELOPED_IN_ANY_PHYSICAL_SYSTEM,_AND_WITH_MAGNETIC_SATURATION_NEGLECTED,_ACTS_IN_SUCH_A_DIRECTION_AS_TO_TEND_TO_____________?$ |
| A. | decrease both the reluctance and inductance |
| B. | increase both the reluctance and inductance |
| C. | decrease the reluctance and increase the inductance |
| D. | increase the reluctance and decrease the inductance |
| Answer» D. increase the reluctance and decrease the inductance | |
| 2. |
Electromagnetic_force_and/or_torque_developed_in_any_physical_system,_acts_in_such_a_direction_as_to_tend_to_____________$ |
| A. | increase both the field energy and co-energy at constant current |
| B. | increase the field energy and decrease the co-energy at constant current |
| C. | decrease both the field energy and co-energy at constant current |
| D. | decrease the field energy and increase the co-energy at constant current |
| Answer» B. increase the field energy and decrease the co-energy at constant current | |
| 3. |
Consider a magnetic relay with linear magnetization curve in both of its open and closed position. What happens to the electrical energy input to the relay, when the armature moves slowly from open position to closed position ? |
| A. | W<sub>elec</sub>=W<sub>fld</sub> |
| B. | W<sub>elec</sub>=W<sub>mech</sub> |
| C. | W<sub>elec</sub>=W<sub>mech</sub>/2+W<sub>fld</sub>/2 |
| D. | W<sub>elec</sub>=0 |
| Answer» D. W<sub>elec</sub>=0 | |
| 4. |
The electromagnetic force developed in any physical system acts in such a direction as to tend to _____________ |
| A. | decrease the co-energy at constant mmf |
| B. | increase the co-energy at constant flux |
| C. | decrease the co-energy at constant flux |
| D. | increase the co-energy at constant mmf |
| Answer» E. | |
| 5. |
The electromagnetic force and/or torque, developed in any physical system, acts in such a direction as to tend to ____________ |
| A. | decrease the magnetic stored energy at constant mmf |
| B. | decrease the magnetic stored energy at constant flux |
| C. | increase the magnetic stored energy at constant flux |
| D. | increase the magnetic stored energy at constant current |
| Answer» C. increase the magnetic stored energy at constant flux | |
| 6. |
For a linear electromagnetic circuit, which of the following statement is true? |
| A. | Field energy is less than the Co-energy |
| B. | Field energy is equal to the Co-energy |
| C. | Field energy is greater than the Co-energy |
| D. | Co-energy is zero |
| Answer» C. Field energy is greater than the Co-energy | |
| 7. |
When a current of 5A flows through a coil of linear magnetic circuit, it has flux linkages of 2.4 wb-turns. What is the energy stored in the magnetic field of this coil in Joules? |
| A. | 6 |
| B. | 12 |
| C. | 1.2 |
| D. | 2.4 |
| Answer» B. 12 | |
| 8. |
The energy stored in a magnetic field is given by ____________ where L=self-inductance and Rl=reluctance. |
| A. | 1/2 Li<sup>2</sup> |
| B. | 1/2 (mmf*Rl)<sup>2</sup> |
| C. | 1/2‚àÖRl |
| D. | 1/2 φ<sup>2</sup>i |
| Answer» B. 1/2 (mmf*Rl)<sup>2</sup> | |
| 9. |
Magnetic stored energy density for iron is given by ______ |
| A. | 1/2 B/μ |
| B. | 1/2 B<sup>2</sup> μ |
| C. | 1/2 ‚àÖ<sup>2</sup> Rl |
| D. | 1/2 B<sup>2</sup>/μ |
| Answer» E. | |
| 10. |
For a toroid to extract the energy from the supply system, the flux linkages of the magnetic field must be ________ |
| A. | zero |
| B. | changing or varying |
| C. | constant |
| D. | any of the mentioned |
| Answer» C. constant | |