MCQOPTIONS
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MCQOPTIONS
This section includes 79 Mcqs, each offering curated multiple-choice questions to sharpen your Electrical Engineering knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
What is the reluctance of the circuit in problem 9 if the flux is 275 Wb? |
| A. | 0.0066 At/Wb |
| B. | 0.066 At/Wb |
| C. | 8,727 At/Wb |
| D. | 872 At/Wb |
| Answer» D. 872 At/Wb | |
| 2. |
There is 900 mA of current through a wire with 40 turns. What is the reluctance of the circuit if the flux is 400 Wb? |
| A. | 14,400 At/Wb |
| B. | 1,440 At/Wb |
| C. | 9,000 At/Wb |
| D. | 90,000 At/Wb |
| Answer» E. | |
| 3. |
What is the reluctance of a material that has a length of 0.07 m, a cross-sectional area of 0.014 m, and a permeability of 4,500 Wb/At × m? |
| A. | 1111 At/Wb |
| B. | 111 At/Wb |
| C. | 11 At/Wb |
| D. | 1 At/Wb |
| Answer» B. 111 At/Wb | |
| 4. |
The voltage induced across a certain coil is 200 mV. A 120 resistor is connected to the coil terminals. The induced current is |
| A. | 1.7 mA |
| B. | 16 mA |
| C. | 12 mA |
| D. | 120 mA |
| Answer» B. 16 mA | |
| 5. |
Which of the following is expected to have the maximum permeability ? |
| A. | rass |
| B. | opper |
| C. | inc |
| D. | bonite |
| Answer» E. | |
| 6. |
The attraction capacity of electromagnet will increase if the |
| A. | ore length increases i |
| B. | ore area increases |
| C. | lux density decreases |
| D. | lux density increases |
| Answer» E. | |
| 7. |
The main constituent of permalloy is |
| A. | obalt |
| B. | hromium |
| C. | ickel |
| D. | ungsten |
| Answer» D. ungsten | |
| 8. |
The initial permeability of an iron rod is |
| A. | he highest permeability of the iron rod |
| B. | he lowest permeability of the iron rod |
| C. | he permeability at the end of the iron rod |
| D. | he permeability almost in non-magnetised state |
| Answer» E. | |
| 9. |
The working of a meter is based on the use of a permanent magnet. In order to protect the meter functioning from stray magnetic fields |
| A. | eter is surrounded by strong magnetic fields |
| B. | soft iron shielding is used |
| C. | plastic shielding is provided |
| D. | shielding of anon-magnetic material is used |
| Answer» C. plastic shielding is provided | |
| 10. |
The uniform magnetic field is |
| A. | he field of a set of parallel conductors |
| B. | he field of a single conductor |
| C. | he field in which all lines of magnetic flux are parallel and equidistant |
| D. | one of the above |
| Answer» D. one of the above | |
| 11. |
Ferrites are materials. |
| A. | aramagnetic |
| B. | iamagnetic |
| C. | erromagnetic |
| D. | one of the above |
| Answer» D. one of the above | |
| 12. |
The commonly used material for shielding or screening magnetism is |
| A. | opper |
| B. | luminium |
| C. | oft iron |
| D. | rass |
| Answer» D. rass | |
| 13. |
The unit of relative permeability is |
| A. | enry/metre |
| B. | enry |
| C. | enry/sq. m |
| D. | t is dimensionless |
| Answer» E. | |
| 14. |
If a copper disc is rotated rapidly below a freely suspended magnetic needle, the magnetic needle shall start rotating with a velocity |
| A. | ess than that of disc but in opposite direction |
| B. | qual to that of disc and in the same direction |
| C. | qual to that of disc and in the opposite direction |
| D. | ess than that of disc and in the same direction |
| Answer» E. | |
| 15. |
The electromagnet has 50 turns and a current of 1A flows through the coil. If the length of the magnet circuit is 200 mm, what is the magnetic field strength? |
| A. | 500 AT/m |
| B. | 50 AT/m |
| C. | 5 AT/m |
| D. | .5 AT/m |
| Answer» C. 5 AT/m | |
| 16. |
The bar magnet has |
| A. | he dipole moment |
| B. | onopole moment |
| C. | and (B) both |
| D. | one of the above |
| Answer» B. onopole moment | |
| 17. |
Out of the following statements, concerning an electric field, which statement is not true? |
| A. | he electric intensity is a vector quantity |
| B. | he electric field intensity at a point is numerically equal to the force exerted upon a charge placed at that point |
| C. | n electric field is defined as a point in space at which an electric charge would experience a force |
| D. | nit field intensity in the exertion of a force of one newton on a charge of one coulomb |
| Answer» C. n electric field is defined as a point in space at which an electric charge would experience a force | |
| 18. |
The force between two long parallel conductors is inversely proportional to |
| A. | adius of conductors |
| B. | urrent in one conductor |
| C. | roduct of current in two conductors |
| D. | istance between the conductors |
| Answer» E. | |
| 19. |
Ferrites are a sub-group of |
| A. | on-magnetic materials |
| B. | erro-magnetic materials |
| C. | aramagnetic materials |
| D. | erri-magnetic materials |
| Answer» E. | |
| 20. |
The most effective and quickest may of making a magnet from soft iron is by |
| A. | lacing it inside a coil carrying current |
| B. | nduction |
| C. | he use of permanent magnet |
| D. | ubbing with another magnet |
| Answer» B. nduction | |
| 21. |
Main causes of noisy solenoid are |
| A. | trong tendency of fan out of laminations at the end caused by repulsion among magnetic lines of force |
| B. | neven bearing surface, caused by dirt or uneven wear between moving and stationary parts |
| C. | oth of above |
| D. | one of the above |
| Answer» D. one of the above | |
| 22. |
Which of the following type of materials are not very important for engineering applications? |
| A. | erromagnetic |
| B. | aramagnetic |
| C. | iamagnetic |
| D. | one of the above |
| Answer» D. one of the above | |
| 23. |
The Biotsavart's law is a general modification of |
| A. | irchhoff's law |
| B. | enz's law |
| C. | mpere's law |
| D. | araday's laws |
| Answer» D. araday's laws | |
| 24. |
In the left hand rule, forefinger always represents |
| A. | oltage |
| B. | urrent |
| C. | agnetic field |
| D. | irection of force on the conductor |
| Answer» D. irection of force on the conductor | |
| 25. |
For which of the following materials the net magnetic moment should be zero? |
| A. | iamagnetic materials |
| B. | errimagnetic materials |
| C. | ntiferromagnetic materials |
| D. | ntiferrimagnetic materials |
| Answer» D. ntiferrimagnetic materials | |
| 26. |
In a simple magnetic field the strength of magnet flux |
| A. | s constant and has same value in energy part of the magnetic field |
| B. | ncreases continuously from initial value to final value |
| C. | ecreases continuously from initial value to final value |
| D. | irst increases and then decreases till it becomes zero |
| Answer» E. | |
| 27. |
Two infinitely long parallel conductors in vacuum any separated 1 metre between centers >then a current of 1 ampere flows the. uk each conductor, produce on each other a force of |
| A. | x 1(T2 N/m) |
| B. | x KT3 N/m |
| C. | x 10"5 N/m |
| D. | x 1(T7 N/m) |
| Answer» E. | |
| 28. |
A keeper is used to |
| A. | hange the direction of magnetic lines |
| B. | mplify flux |
| C. | estore lost flux |
| D. | rovide a closed path for flux |
| Answer» E. | |
| 29. |
The left hand rule correlates to |
| A. | urrent, induced e.m.f. and direction of force on a conductor |
| B. | agnetic field, electric field and direction of force on a conductor |
| C. | elf induction, mutual induction and direction of force on a conductor |
| D. | urrent, magnetic field and direction of force on a conductor |
| Answer» E. | |
| 30. |
The magnetic reluctance of a material |
| A. | ecreases with increasing cross sectional area of material |
| B. | ncreases with increasing cross-sec-tional area of material |
| C. | oes not vary with increasing cross-sectional area of material |
| D. | ny of the above |
| Answer» B. ncreases with increasing cross-sec-tional area of material | |
| 31. |
Two long parallel conductors carry 100 A. If the conductors are separated by 20 mm, the force per meter of length of each conductor will be |
| A. | 00 N |
| B. | 0 N |
| C. | N |
| D. | .1 N |
| Answer» E. | |
| 32. |
The stray line of magnetic flux is defined as |
| A. | line vertical to the flux lines |
| B. | he mean length of a ring shaped coil |
| C. | line of magnetic flux in a non-uniform field |
| D. | line of magnetic flux which does not follow the designed path |
| Answer» E. | |
| 33. |
The relative permeability of materials is not constant. |
| A. | iamagnetic |
| B. | aramagnetic |
| C. | erromagnetic |
| D. | nsulating |
| Answer» D. nsulating | |
| 34. |
Hysteresis loop in case of magnetically hard materials is more in shape as compared to magnetically soft materials. |
| A. | ircular |
| B. | riangular |
| C. | ectangular |
| D. | one of the above |
| Answer» D. one of the above | |
| 35. |
The magnetism left in the iron after exciting field has been removed is known as |
| A. | ermeance |
| B. | esidual magnetism |
| C. | usceptance |
| D. | eluctance |
| Answer» C. usceptance | |
| 36. |
One maxwell is equal to |
| A. | 0-8 webers |
| B. | 0-4 webers |
| C. | 08 webers |
| D. | 04 webers |
| Answer» E. | |
| 37. |
Temporary magnets are used in |
| A. | oud-speakers |
| B. | enerators |
| C. | otors |
| D. | ll of the above |
| Answer» E. | |
| 38. |
When an iron piece is placed in a magnetic field |
| A. | he magnetic lines of force will bend away from their usual paths in order to go away from the piece |
| B. | he magnetic lines of force will bend away from their usual paths in order to pass through the piece |
| C. | he magnetic field will not be affected |
| D. | he iron piece will break |
| Answer» C. he magnetic field will not be affected | |
| 39. |
What will be the magnetic potential difference across the air gap of 2 cm length in magnetic field of 200 AT/m? |
| A. | AT |
| B. | AT |
| C. | AT |
| D. | 0 AT |
| Answer» C. AT | |
| 40. |
The two conductors of a transmission line carry equal current I in opposite directions. The force on each conductor is |
| A. | roportional to 7 |
| B. | roportional to X |
| C. | roportional to distance between the conductors |
| D. | nversely proportional to I |
| Answer» C. roportional to distance between the conductors | |
| 41. |
Which of the following is a ferromagnetic material? |
| A. | ungsten |
| B. | luminium |
| C. | opper |
| D. | ickel |
| Answer» E. | |
| 42. |
Air gap has_______eluctance as compared to iron or steel path |
| A. | ittle |
| B. | ower |
| C. | igher |
| D. | ero |
| Answer» C. igher | |
| 43. |
Degaussing is the process of |
| A. | emoval of magnetic impurities |
| B. | emoving gases from the materials |
| C. | emagnetising metallic parts |
| D. | emagnetising metallic parts |
| Answer» E. | |
| 44. |
The materials are a bit inferior conductors of magnetic flux than air. |
| A. | erromagnetic |
| B. | aramagnetic |
| C. | iamagnetic |
| D. | ielectric |
| Answer» D. ielectric | |
| 45. |
The susceptibility of paramagnetic materials generally lies between |
| A. | T3 and 1CT6 |
| B. | CT3 and 1CT7 |
| C. | T4 and KT8 |
| D. | 0"2 and KT5 |
| Answer» B. CT3 and 1CT7 | |
| 46. |
A certain amount of current flows through a ring shaped coil with fixed number of turns. How does the magnetic induction B varies inside the coil if an iron core is threaded into coil without dimensional change of coil? |
| A. | ecreases |
| B. | ncreases |
| C. | emains same |
| D. | irst increases and then decreases depending on the depth of iron in¬sertion |
| Answer» C. emains same | |
| 47. |
Magnetic moment is a |
| A. | ole strength |
| B. | niversal constant |
| C. | calar quantity |
| D. | ector quantity |
| Answer» E. | |
| 48. |
For which of the following materials the saturation value is the highest? |
| A. | erromagnetic materials |
| B. | aramagnetic materials |
| C. | iamagnetic materials |
| D. | errites |
| Answer» E. | |
| 49. |
Magnetising steel is normals difficult because |
| A. | t corrodes easily |
| B. | t has high permeability |
| C. | t has high specific gravity |
| D. | t has low permeability |
| Answer» E. | |
| 50. |
Which of the following materials are diamagnetic? |
| A. | ilver |
| B. | opper |
| C. | ilver and copper |
| D. | ron |
| Answer» D. ron | |