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Home⇒ Engineering⇒
Electromagnetic field theory
1-Dont try to cram or spend more time here just read it fast and cover syllabus then practice MCQ's cheptor of same topic to check your progress. . |
2-Wrong options are also given but dont concentrate there, Right answer is in bold format. |
Q21 ⇒ The best excited reflector from a wave guide is horn [other wrong options] [Discuss in forum] parabolic biconical corner |
Q22 ⇒ Good smoothing factor of a coil depends on property of the wire of the coil [other wrong options] [Discuss in forum] inductance of the coil terminal voltage cross-sectional area of the wire of the coil |
Q23 ⇒ Which layer is least important in high frequency propagation? D layer [other wrong options] [Discuss in forum] E layer F1 layer F2 layer |
Q24 ⇒ Which of the following is abnormal variation in ionosphere? Ionospheric storms [other wrong options] [Discuss in forum] Diurnal variation Seasonal variation None of the above |
Q25 ⇒ Distances near the skip distance should be used for sky-wave propagation to prevent sky-wave and upper ray interference [other wrong options] [Discuss in forum] to avoid the Faraday effect to avoid tilting so as to exceed the critical frequency |
Q26 ⇒ A TEM wave incident obliquely on a dielectric boundary with εr1 = 2 and εr2 = 1, the angle of incidence for total reflection is 45° [other wrong options] [Discuss in forum] 30° 60° 90° |
Q27 ⇒ Diffraction of electromagnetic wave may occur around the edge of a sharp obstacle [other wrong options] [Discuss in forum] is caused by reflection from the ground arises only with spherical wavefronts none of these |
Q28 ⇒ In waveguide Degenerate modes are two mode having same cut off frequency [other wrong options] [Discuss in forum] two mode having same power two mode having same phase velocity it is a hypothetical mode |
Q29 ⇒ Characteristic wave impedance is (ε/μ)1/2 [other wrong options] [Discuss in forum] ε/μ Ex/Hy Hy/Ex |
Q30 ⇒ The directive gain of λ/2 resonant wire is 1.64. TRUE [other wrong options] [Discuss in forum] FALSE |
Q31 ⇒ An electromagnetic wave incident on a perfect conductor is entirely reflected [other wrong options] [Discuss in forum] fully transmitted partially transmitted none of the above |
Q32 ⇒ Tropospheric scatter is used with frequencies in the UHF [other wrong options] [Discuss in forum] HF VHF VLF |
Q33 ⇒ The electric intensity for free space is given by σ.ε0 [other wrong options] [Discuss in forum] ε0d σ/ε0 d/ε0 |
Q34 ⇒ When the phase velocity of an EM wave depends on frequency in any medium the phenomenon is called polarisation [other wrong options] [Discuss in forum] scattering absorption dispersion |
Q35 ⇒ Which of the following statement is incorrect? None of the above [other wrong options] [Discuss in forum] Curl of vector potential is magnetic field density Electric charges in motion produce magnetic field Electric charges at rest produce electrostatic field |
Q36 ⇒ The virtual height of an ionospheric layer is __________ true height higher than [other wrong options] [Discuss in forum] equal to less than no relation |
Q37 ⇒ The essential condition for antenna array to be linear is that individual antennas of the array must be equally spaced along a straight line [other wrong options] [Discuss in forum] individual antennas of the array must be of equal size any two individual antennas of the array must not be in the same direction none of the above |
Q38 ⇒ The relative permittivity of the ionosphere at ratio frequencies is < 1 [other wrong options] [Discuss in forum] > 1 1 ≥ 1 |
Q39 ⇒ For satellite communication, the frequency should be more than the critical frequency [other wrong options] [Discuss in forum] equal to the critical frequency less than the critical frequency none of these |
Q40 ⇒ In a perfect conductor the incident and reflected wave combine to produce a standing wave which is not progressing [other wrong options] [Discuss in forum] a stronger incident wave a stronger reflected wave none of the above |
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