Antennas - MCQ Test


15 Questions MCQ Test Mock Tests Electronics & Communication Engineering GATE 2020 | Antennas - MCQ Test


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This mock test of Antennas - MCQ Test for Railways helps you for every Railways entrance exam. This contains 15 Multiple Choice Questions for Railways Antennas - MCQ Test (mcq) to study with solutions a complete question bank. The solved questions answers in this Antennas - MCQ Test quiz give you a good mix of easy questions and tough questions. Railways students definitely take this Antennas - MCQ Test exercise for a better result in the exam. You can find other Antennas - MCQ Test extra questions, long questions & short questions for Railways on EduRev as well by searching above.
QUESTION: 1

A Hertizian dipole at the origin in free space has dl = 10 cm and I = 20 cos (2π x 107t) A. The E at the distant point (100, 0, 0) is

Solution:

QUESTION: 2

A 25 A source operating at 300 MHz feeds a Hertizian dipole of length 4 mm situated at the origin. Consider the point P(10, 30o,90o).

Que: The H at point P is

Solution:

QUESTION: 3

A 25 A source operating at 300 MHz feeds a Hertizian dipole of length 4 mm situated at the origin. Consider the point P(10, 30o,90o).

Que: The E at point P is

Solution:

QUESTION: 4

An antenna can be modeled as an electric dipole of length 4 m at 3 MHz. If current is uniform over its length, then radiation resistance of the antenna is

Solution:

QUESTION: 5

A antenna located on the surface of a flat earth transmit an average power of 150 kW. Assume that all the power is radiated uniformly over the surface of hemisphere with the antenna at the center. The time-average poynting vector at 50 km is

Solution:

QUESTION: 6

An L-band pulse radar has common transmitting and receiving antenna. The antenna having directive gain of 36 dB operates at 1.5 GHz and transmits 200 kW. The object is 120 km from the radar and its scattering cross section is 8 m2 

Que: The magnitude of the incident electric field intensity of the object is

Solution:

Gd = 36 dB = 3981

QUESTION: 7

An L-band pulse radar has common transmitting and receiving antenna. The antenna having directive gain of 36 dB operates at 1.5 GHz and transmits 200 kW. The object is 120 km from the radar and its scattering cross section is 8 m2 

Que: The magnitude of the scattered electric field at the radar is

Solution:

QUESTION: 8

A transmitting antenna with a 300 MHz carrier frequency produces 2 kW of power. If both antennas has unity power gain, the power received by another antenna at a distance of 1 km is

Solution:

QUESTION: 9

A bistatic radar system shown in fig. has following parameters: f = 5 GHz, Gdt = 34 dB, Gdr = 22 dB. To obtain a return power of 8 pW the minimum necessary radiated power is

Solution:

QUESTION: 10

The radiation resistance of an antenna is 63Ω and loss resistance 7Ω If antenna has power gain of 16, then directivity is

Solution:

QUESTION: 11

An antenna is desired to operate on a frequency of 40 MHz whose quality factor is 50. The bandwidth of antenna is

Solution:

QUESTION: 12

A thin dipole antenna is  λ/15 long. If its loss resistance is 1.2 Ω, the efficiency is

Solution:

QUESTION: 13

An array comprises of two dipoles that are separated by the wavelength. The dipoles are fed by currents of the same magnitude and phase.

Que: The array factor is

Solution:

QUESTION: 14

An array comprises of two dipoles that are separated by the wavelength. The dipoles are fed by currents of the same magnitude and phase.

Que: The nulls of the pattern occur when θ is

Solution:

cos (πcosθ) = 0

QUESTION: 15

An array comprises of two dipoles that are separated by the wavelength. The dipoles are fed by currents of the same magnitude and phase.

Que: The maximum of the pattern occur at

Solution:

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