MCQOPTIONS
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MCQOPTIONS
This section includes 682 Mcqs, each offering curated multiple-choice questions to sharpen your Electrical Engineering knowledge and support exam preparation. Choose a topic below to get started.
| 301. |
The unit of magnetic flux is |
| A. | henry |
| B. | weber |
| C. | ampereturn/weber |
| D. | ampere/metre |
| Answer» C. ampereturn/weber | |
| 302. |
The relative permeability of a ferromagnetic material is |
| A. | less than one |
| B. | more than one |
| C. | more than 10 |
| D. | more than 100 or 1000 |
| Answer» E. | |
| 303. |
An air gap is usually inserted in magnetic circuits to |
| A. | increase m.m.f. |
| B. | increase the flux |
| C. | prevent saturation |
| D. | none of the above |
| Answer» D. none of the above | |
| 304. |
Magnetism of a magnet can be destroyed by |
| A. | heating |
| B. | hammering |
| C. | by inductive action of another magnet |
| D. | by all above methods |
| Answer» E. | |
| 305. |
Main causes of noisy solenoid are |
| A. | strong tendency of fan out of lami-nations at the end caused by repul¬sion among magnetic lines of force |
| B. | uneven bearing surface, caused by dirt or uneven wear between moving and stationary parts |
| C. | both of above |
| D. | none of the above |
| Answer» D. none of the above | |
| 306. |
Temporary magnets are used in |
| A. | loud-speakers |
| B. | generators |
| C. | motors |
| D. | all of the above |
| Answer» E. | |
| 307. |
The attraction capacity of electromagnet will increase if the |
| A. | core length increases i |
| B. | core area increases |
| C. | flux density decreases |
| D. | flux density increases |
| Answer» E. | |
| 308. |
For which of the following materials the net magnetic moment should be zero ? |
| A. | diamagnetic materials |
| B. | ferrimagnetic materials |
| C. | antiferromagnetic materials |
| D. | antiferrimagnetic materials |
| Answer» D. antiferrimagnetic materials | |
| 309. |
Which of the following type of materials are not very important for engineering applications ? |
| A. | ferromagnetic |
| B. | paramagnetic |
| C. | diamagnetic |
| D. | none of the above |
| Answer» D. none of the above | |
| 310. |
Which of the following materials are dia-magnetic ? |
| A. | silver |
| B. | copper |
| C. | silver and copper |
| D. | iron |
| Answer» D. iron | |
| 311. |
The susceptibility of paramagnetic materials generally lies between |
| A. | kt3 and 1ct6 |
| B. | 1ct3 and 1ct7 |
| C. | kt4 and kt8 |
| D. | 10"2 and kt5 |
| Answer» B. 1ct3 and 1ct7 | |
| 312. |
The bar magnet has |
| A. | the dipole moment |
| B. | monopole moment |
| C. | (a) and (b) both |
| D. | none of the above |
| Answer» B. monopole moment | |
| 313. |
The stray line of magnetic flux is defined as |
| A. | a line vertical to the flux lines |
| B. | the mean length of a ring shaped coil |
| C. | a line of magnetic flux in a non-uniform field |
| D. | a line of magnetic flux which does not follow the designed path |
| Answer» E. | |
| 314. |
How does the magnetic compass needle behave in a magnetic field ? |
| A. | it assures a position right angle to magnetic field |
| B. | it starts rotating |
| C. | it assures a position which follows a line of magnetic flux |
| D. | none of the above |
| Answer» D. none of the above | |
| 315. |
The initial permeability of an iron rod is |
| A. | the highest permeability of the iron rod |
| B. | the lowest permeability of the iron rod |
| C. | the permeability at the end of the iron rod |
| D. | the permeability almost in non-magnetised state |
| Answer» E. | |
| 316. |
What will be the magnetic potential difference across the air gap of 2 cm length in magnetic field of 200 AT/m ? |
| A. | 2 at |
| B. | 4 at |
| C. | 6 at |
| D. | 10 at |
| Answer» C. 6 at | |
| 317. |
What will be the current passing through the ring shaped air cored coil when number of turns is 800 and ampere turns are 3200 ? |
| A. | 2 |
| B. | 4 |
| C. | 6 |
| D. | 8 |
| Answer» C. 6 | |
| 318. |
The magneto-motive force is |
| A. | the voltage across the two ends of exciting coil |
| B. | the flow of an electric current |
| C. | the sum of all currents embraced by one line of magnetic field |
| D. | the passage of magnetic field through an exciting coil |
| Answer» D. the passage of magnetic field through an exciting coil | |
| 319. |
The uniform magnetic field is |
| A. | the field of a set of parallel conductors |
| B. | the field of a single conductor |
| C. | the field in which all lines of mag¬netic flux are parallel and equidis¬tant |
| D. | none of the above |
| Answer» D. none of the above | |
| 320. |
The change of cross-sectional area of conductor in magnetic field will affect |
| A. | reluctance of conductor |
| B. | resistance of conductor |
| C. | (a) and (b) b >th in the same way |
| D. | none of the above |
| Answer» D. none of the above | |
| 321. |
A keeper is used to |
| A. | change the direction of magnetic lines |
| B. | amplify flux |
| C. | restore lost flux |
| D. | provide a closed path for flux |
| Answer» E. | |
| 322. |
Hysteresis loop in case of magnetically hard materials is more in shape as compared to magnetically soft materials. |
| A. | circular |
| B. | triangular |
| C. | rectangular |
| D. | none of the above |
| Answer» D. none of the above | |
| 323. |
The materials are a bit inferior conductors of magnetic flux than air. |
| A. | ferromagnetic |
| B. | paramagnetic |
| C. | diamagnetic |
| D. | dielectric |
| Answer» D. dielectric | |
| 324. |
The relative permeability of materials is not constant. |
| A. | diamagnetic |
| B. | paramagnetic |
| C. | ferromagnetic |
| D. | insulating |
| Answer» D. insulating | |
| 325. |
A permanent magnet |
| A. | attracts some substances and repels others |
| B. | attracts all paramagnetic substan¬ces and repels others |
| C. | attracts only ferromagnetic sub¬stances |
| D. | attracts ferromagnetic substances and repels all others |
| Answer» B. attracts all paramagnetic substan¬ces and repels others | |
| 326. |
The retentivity (a property) of material is useful for the construction of |
| A. | permanent magnets |
| B. | transformers |
| C. | non-magnetic substances |
| D. | electromagnets |
| Answer» B. transformers | |
| 327. |
If a copper disc is rotated rapidly below a freely suspended magnetic needle, the magnetic needle shall start rotating with a velocity |
| A. | less than that of disc but in opposite direction |
| B. | equal to that of disc and in the same direction |
| C. | equal to that of disc and in the opposite direction |
| D. | less than that of disc and in the same direction |
| Answer» E. | |
| 328. |
The commonly used material for shielding or screening magnetism is |
| A. | copper |
| B. | aluminium |
| C. | soft iron |
| D. | brass |
| Answer» D. brass | |
| 329. |
The most effective and quickest may of making a magnet from soft iron is by |
| A. | placing it inside a coil carrying current |
| B. | induction |
| C. | the use of permanent magnet |
| D. | rubbing with another magnet |
| Answer» B. induction | |
| 330. |
The Biot-savart's law is a general modification of |
| A. | kirchhoffs law |
| B. | lenz\s law |
| C. | ampere\s law |
| D. | faraday\s laws |
| Answer» D. faraday\s laws | |
| 331. |
Unit for quantity of electricity is |
| A. | ampere-hour |
| B. | watt |
| C. | joule |
| D. | coulomb |
| Answer» E. | |
| 332. |
The unit of flux is the same as that of |
| A. | reluctance |
| B. | resistance |
| C. | permeance |
| D. | pole strength |
| Answer» E. | |
| 333. |
A square cross-sectional magnet has a pole strength of 1 x 10 Wb and cross sectional area of 20 mm x 20 mm. What is the strength at a distance of 100 mm from the unit pole in air ? |
| A. | 63.38 n/wb |
| B. | 633.8 n/wb |
| C. | 6338 n/wb |
| D. | 63380 n/wb |
| Answer» D. 63380 n/wb | |
| 334. |
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. | 2500 at/m |
| B. | 250 at/m |
| C. | 25 at/m |
| D. | 2.5 at/m |
| Answer» C. 25 at/m | |
| 335. |
Two long parallel conductors carry 100 A. If the conductors are separated by 20 mm, the force per metre of length of each conductor will be |
| A. | 100 n |
| B. | 10 n |
| C. | 1 n |
| D. | 0.1 n |
| Answer» E. | |
| 336. |
Susceptibility is positive for |
| A. | non-magnetic substances |
| B. | diamagnetic substances |
| C. | ferromagnetic substances |
| D. | none of the above |
| Answer» D. none of the above | |
| 337. |
When two ends of a circular uniform wire are joined to the terminals of a battery, the field at the centre of the circle |
| A. | will be zero |
| B. | will be infinite |
| C. | will depend on the amount of e.m.f. applied |
| D. | will depend on the radius of the circle |
| Answer» E. | |
| 338. |
One maxwell is equal to |
| A. | 10 webers |
| B. | 10 webers |
| C. | 10 webers |
| D. | 10 webers |
| Answer» E. | |
| 339. |
Out of the following statements, concerning an electric field, which statement is not true ? |
| A. | the electric intensity is a vector quantity |
| B. | the electric field intensity at a point is numerically equal to the force exerted upon a charge placed at that point |
| C. | an electric field is defined as a point in space at which an electric charge would experienc* a force |
| D. | unit field intensity in the exertion of a force of one newton on a charge of one coulomb |
| Answer» C. an electric field is defined as a point in space at which an electric charge would experienc* a force | |
| 340. |
When a magnet is in motion relative to a coil the induced e.m.f. does not depend upon |
| A. | resistance of the coil |
| B. | motion of the magnet |
| C. | number of turns of the coil |
| D. | pole strength of the magnet |
| Answer» B. motion of the magnet | |
| 341. |
One telsa is equal to |
| A. | 1 wb/mm2 |
| B. | 1 wb/m |
| C. | 1 wb/m2 |
| D. | 1 mwb/m2 |
| Answer» D. 1 mwb/m2 | |
| 342. |
Which of the following is expected to have the maximum permeability ? |
| A. | brass |
| B. | copper |
| C. | zinc |
| D. | ebonite |
| Answer» E. | |
| 343. |
Which of the following is not a unit of flux? |
| A. | maxwell |
| B. | telsa |
| C. | weber |
| D. | all of the above |
| Answer» C. weber | |
| 344. |
The magnetism left in the iron after exciting field has been removed is known as |
| A. | permeance |
| B. | residual magnetism |
| C. | susceptance |
| D. | reluctance |
| Answer» C. susceptance | |
| 345. |
Which of the following is the unit of magnetic flux density ? |
| A. | weber |
| B. | lumens |
| C. | tesla |
| D. | none of the above |
| Answer» D. none of the above | |
| 346. |
The relative permeability is less than unity is case of |
| A. | ferromagnetic materials |
| B. | ferrites |
| C. | non-ferrous materials |
| D. | diamagnetic materials |
| Answer» E. | |
| 347. |
Reciprocal of permeability is |
| A. | reluctivity |
| B. | susceptibility |
| C. | permittivity |
| D. | conductance |
| Answer» B. susceptibility | |
| 348. |
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. | meter is surrounded by strong magnetic fields |
| B. | a soft iron shielding is used |
| C. | a plastic shielding is provided |
| D. | a shielding of anon-magnetic material is used |
| Answer» C. a plastic shielding is provided | |
| 349. |
Gilbert is a unit of |
| A. | electromotive force |
| B. | magnetomotive force |
| C. | conductance |
| D. | permittivity |
| Answer» C. conductance | |
| 350. |
Ferrites are a sub-group of |
| A. | non-magnetic materials |
| B. | ferro-magnetic materials |
| C. | paramagnetic materials |
| D. | ferri-magnetic materials |
| Answer» E. | |