MCQOPTIONS
Saved Bookmarks
MCQOPTIONS
This section includes 9294 Mcqs, each offering curated multiple-choice questions to sharpen your Engineering knowledge and support exam preparation. Choose a topic below to get started.
| 1351. |
Magnetic susceptibility of a medium is the ratio of |
| A. | magnetic field strength to mmf |
| B. | intensity of magnetization to magnetic flux density |
| C. | intensity of magnetization to field strength |
| D. | mmf to magnetic field strength |
| Answer» D. mmf to magnetic field strength | |
| 1352. |
The phase velocity in a coaxial line is |
| A. | greater than C |
| B. | equal to C |
| C. | less than C |
| D. | not depend on C |
| Answer» B. equal to C | |
| 1353. |
The ionosphere plays a significant role in radio wave propagation at |
| A. | high frequency |
| B. | ultra-high frequencies |
| C. | microwave frequency |
| D. | optical frequencies |
| Answer» B. ultra-high frequencies | |
| 1354. |
Radiation resistance for wire antenna is |
| A. | 55 Ω |
| B. | 65 Ω |
| C. | 100 Ω |
| D. | 377 Ω |
| Answer» C. 100 Ω | |
| 1355. |
Antenna is a __________ element |
| A. | passive |
| B. | active |
| C. | resistive |
| D. | capacitive |
| Answer» B. active | |
| 1356. |
The gain of an half wavelength antenna is |
| A. | 2.15 dB |
| B. | 10 dB |
| C. | 1.78 dB |
| D. | 100 dB |
| Answer» B. 10 dB | |
| 1357. |
Gain of isotropic antenna is |
| A. | 10 dB |
| B. | 0 dB |
| C. | |
| D. | 1 dB |
| Answer» B. 0 dB | |
| 1358. |
In end fire array the principle direction of radiation |
| A. | is perpendicular to the array axis |
| B. | is perpendicular to the array axis and also to the plane containing the array elements |
| C. | coincides with the direction of the array |
| D. | is at 45 to the direction of array axis |
| Answer» D. is at 45 to the direction of array axis | |
| 1359. |
A parabolic antenna produces a radiation pattern which is |
| A. | circularly polarized |
| B. | highly directional |
| C. | omnidirectional |
| D. | linearly polarized |
| Answer» C. omnidirectional | |
| 1360. |
The numerical value of directive gain may lie between |
| A. | 1 and + 1 |
| B. | 0 and 1 |
| C. | 0 and |
| D. | 1 and |
| Answer» D. 1 and | |
| 1361. |
The wave propagation occurs without attenuation in case of a |
| A. | conductor |
| B. | semiconductor |
| C. | perfect dielectric |
| D. | none of the above |
| Answer» D. none of the above | |
| 1362. |
A very reliable service has to be established between two points on earth separated by 1000 km. The band that will be used as |
| A. | MF |
| B. | VHF |
| C. | VLF |
| D. | HF |
| Answer» D. HF | |
| 1363. |
A rectangular waveguide (2.29 x 1.02) cm operates at a freq. of 11 GHz in TE10 mode. If the maximum potential gradient of the signal is 5 kV/cm, then the maximum power handling capacity of the waveguide will be |
| A. | 31.11 mW |
| B. | 31.11 W |
| C. | 31.11 kW |
| D. | 31.11 MW |
| Answer» D. 31.11 MW | |
| 1364. |
Considerable ionization occurs between the range |
| A. | 50 km to 400 km |
| B. | 100 to 400 km |
| C. | 50 km to 250 km |
| D. | 10 to 50 km |
| Answer» B. 100 to 400 km | |
| 1365. |
Solution of Laplace equations, which are continuous through the second derivative, are called |
| A. | bessel functions |
| B. | odd functions |
| C. | harmonic functions |
| D. | fundamental functions |
| Answer» D. fundamental functions | |
| 1366. |
The skip distance does not depends upon |
| A. | the power transmitted |
| B. | type of wave propagation |
| C. | angle of beaming of the wave |
| D. | frequency of the signal transmitted |
| Answer» C. angle of beaming of the wave | |
| 1367. |
After reflection from a plane conducting surface, the apparent velocity of electromagnetic wave becomes greater than the velocity of light in free space is called |
| A. | conventional velocity |
| B. | phase velocity |
| C. | propagation velocity |
| D. | group velocity |
| Answer» C. propagation velocity | |
| 1368. |
In a turnstile antenna the crossed dipoles are excited with voltages |
| A. | in phase with each other |
| B. | 90 out of phase with each other |
| C. | 120 out of phase with each other |
| D. | 180 out of phase with each other |
| Answer» C. 120 out of phase with each other | |
| 1369. |
Directivity of antenna is defined as |
| A. | maximum directive gain |
| B. | average directive gain |
| C. | |
| D. | 0 |
| Answer» B. average directive gain | |
| 1370. |
Which of the following does not characterize a ferromagnetic material? |
| A. | Coercivity |
| B. | Permeability |
| C. | Permittivity |
| D. | Reluctance |
| Answer» D. Reluctance | |
| 1371. |
Consider the following; for a loss-less transmission line we can write, Zin = - jz0 for a shorted line with l = /8Zin = j for a shorted line with l = /4Zin= jz0 for an open line with l = /2Zin = 0 for a matched line of any length Select the correct answer using the codes given below codes. |
| A. | 1, 2 |
| B. | 2, 3 |
| C. | 1, 3 |
| D. | 2, 4 |
| Answer» E. | |
| 1372. |
Strip lines are used at |
| A. | microwave frequency |
| B. | low frequency |
| C. | High frequency |
| D. | at any frequency |
| Answer» B. low frequency | |
| 1373. |
For a wave propagating in air filled rectangular waveguide. |
| A. | guide wavelength is never less than free space wavelength. |
| B. | wave impedance is never less than the free space impedance |
| C. | TEM mode is possible if the dimension of the waveguide are properly chosen. |
| D. | propagation constant is a real quantity. |
| Answer» B. wave impedance is never less than the free space impedance | |
| 1374. |
The secondary lobes in binomial arrays can be reduced by |
| A. | maintaining spacing between two consecutive radiating sources less than /2 |
| B. | maintaining the amplitudes in radiating sources, from outer towards the centre source, proportional to the coefficients of the successive terms of the binomial series |
| C. | both (a) and (b) |
| D. | none of the above |
| Answer» D. none of the above | |
| 1375. |
Which of the following statement is incorrect? |
| A. | Curl of vector potential is magnetic field density |
| B. | Electric charges in motion produce magnetic field |
| C. | Electric charges at rest produce electrostatic field |
| D. | None of the above |
| Answer» E. | |
| 1376. |
The energy stored in an electric field is given by |
| A. | <img src="/_files/images/electronics-and-communication-engineering/electromagnetic-field-theory/191-130-1.png"> |
| B. | <img src="/_files/images/electronics-and-communication-engineering/electromagnetic-field-theory/191-130-2.png"> |
| C. | <img src="/_files/images/electronics-and-communication-engineering/electromagnetic-field-theory/191-130-3.png"> |
| D. | <img src="/_files/images/electronics-and-communication-engineering/electromagnetic-field-theory/191-130-4.png"> |
| Answer» B. <img src="/_files/images/electronics-and-communication-engineering/electromagnetic-field-theory/191-130-2.png"> | |
| 1377. |
Which of following antenna produces elliptical polarisation? |
| A. | Helical |
| B. | Parabolic |
| C. | Dipole |
| D. | None |
| Answer» E. | |
| 1378. |
Transverse electric (TE) waves have |
| A. | electric field component E in the direction of propagation |
| B. | magnetic field component H in the direction of propagation |
| C. | magnetic field component H in the direction of propagation and no component of electric field E in this direction |
| D. | electric field component E in the direction of propagation and no component of magnetic field H in this direction |
| Answer» D. electric field component E in the direction of propagation and no component of magnetic field H in this direction | |
| 1379. |
For infinite value of SWR on a transmission line, the line be terminated with impedance as |
| A. | an open-circuit |
| B. | a short-circuit |
| C. | a pure resistance |
| D. | all of the above |
| Answer» E. | |
| 1380. |
An electromagnetic wave incident on a perfect conductor is |
| A. | fully transmitted |
| B. | partially transmitted |
| C. | entirely reflected |
| D. | none of the above |
| Answer» D. none of the above | |
| 1381. |
A time varying magnetic field produces |
| A. | electric field only |
| B. | magnetic field only |
| C. | both magnetic and electric fields |
| D. | none of the above |
| Answer» D. none of the above | |
| 1382. |
The attenuation in waveguides near the cut off frequency is |
| A. | very low |
| B. | very high |
| C. | medium |
| D. | zero |
| Answer» C. medium | |
| 1383. |
The ground waves eventually disappear as one moves away from the transmitter because of |
| A. | tilting |
| B. | maximum single-hop distance limitation |
| C. | interference from the sky waves |
| D. | loss of line-of sight condition |
| Answer» B. maximum single-hop distance limitation | |
| 1384. |
The radiation resistance of a rod tubing antenna is |
| A. | 55 Ω to 60 Ω |
| B. | 60 to 100 Ω |
| C. | 0 to 377 Ω |
| D. | 60 to 200 Ω |
| Answer» B. 60 to 100 Ω | |
| 1385. |
MF is generally used for |
| A. | telegraphy |
| B. | radio and television links |
| C. | satellite communication |
| D. | broadcasting, navigation |
| Answer» E. | |
| 1386. |
Power gain of an antenna in a given direction is the ratio of |
| A. | average power to maximum power |
| B. | radiation intensity in that direction to the total input radiated power |
| C. | radiation intensity in that direction to the average radiated power |
| D. | none of the above |
| Answer» C. radiation intensity in that direction to the average radiated power | |
| 1387. |
If a electromagnetic signal is incident at 0 in a waveguide then at other port of waveguide we will get |
| A. | zero power |
| B. | power |
| C. | depend upon input signal strength |
| D. | depend on frequency |
| Answer» B. power | |
| 1388. |
An antenna having a high Q has |
| A. | lower BW |
| B. | higher BW |
| C. | flat response |
| D. | none of the above |
| Answer» B. higher BW | |
| 1389. |
The polarization of dielectric materials results in |
| A. | production of eddy currents |
| B. | creation of electric dipoles |
| C. | absorption of electrons |
| D. | release of high velocity protons |
| Answer» C. absorption of electrons | |
| 1390. |
A lossless transmission line is connected to two identical voltage source as shown in figure. The impedance measured at the midpoint AA' is |
| A. | |
| B. | 100 |
| C. | 50 |
| D. | 25 |
| Answer» B. 100 | |
| 1391. |
A loss less transmission line is terminated in a load which reflects a part of the incident power. The measured VSWR is 2. The percentage of the power that is reflected back is |
| A. | 57.73 |
| B. | 33.33 |
| C. | 0.11 |
| D. | 11.11 |
| Answer» E. | |
| 1392. |
Measurement of radiation resistance by reflection method is suitable for |
| A. | parasitic element antennas |
| B. | low frequency vertical conductor antenna |
| C. | all type of antennas |
| D. | none of the above |
| Answer» B. low frequency vertical conductor antenna | |
| 1393. |
A higher directivity is specified by |
| A. | high gain low BW (Beamwidth) |
| B. | high gain high BW |
| C. | low gain high BW |
| D. | none of the above |
| Answer» B. high gain high BW | |
| 1394. |
The best excited reflector from a wave guide is |
| A. | horn |
| B. | parabolic |
| C. | biconical |
| D. | corner |
| Answer» B. parabolic | |
| 1395. |
Permeance is analogue to |
| A. | reluctance |
| B. | conductance |
| C. | capacitance |
| D. | resistance |
| Answer» C. capacitance | |
| 1396. |
Which of the following is a better propagation mode to propagate television frequency modulation and radar signals? |
| A. | Satellite communication |
| B. | Ground propagation |
| C. | Polarized communication |
| D. | None of the above |
| Answer» B. Ground propagation | |
| 1397. |
Antenna used for T.V. broadcasting is |
| A. | long dipole |
| B. | metal horn |
| C. | crossed dipole |
| D. | log periodic |
| Answer» D. log periodic | |
| 1398. |
Consider an arbitrary distribution of conducting bodies in a charge free space according to the uniqueness theorem, which of following are required to be specified in order that the field is uniquely determined everywhere? Total charge on each conductorPotential at each conductor surfacePotential at same of conductor and total charge on the remainderTotal charge as well as potential gradient on each conductor surface Select the correct answer using the codes given below codes |
| A. | 1 and 3 |
| B. | 2 and 4 |
| C. | 1, 2, and 3 |
| D. | 1, 2, 3, 4 |
| Answer» C. 1, 2, and 3 | |
| 1399. |
The attenuation constant in case of a transmission line is |
| A. | <img src="/_files/images/electronics-and-communication-engineering/electromagnetic-field-theory/199-301-1.png"> |
| B. | <img src="/_files/images/electronics-and-communication-engineering/electromagnetic-field-theory/199-301-2.png"> |
| C. | <img src="/_files/images/electronics-and-communication-engineering/electromagnetic-field-theory/199-301-3.png"> |
| D. | <img src="/_files/images/electronics-and-communication-engineering/electromagnetic-field-theory/199-301-4.png"> |
| Answer» D. <img src="/_files/images/electronics-and-communication-engineering/electromagnetic-field-theory/199-301-4.png"> | |
| 1400. |
A vertical loop antenna, like a horizontal dipole, is vertically polarised. |
| A. | True |
| B. | False |
| Answer» C. | |