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Test: Communication System- 1

25 Questions MCQ Test Basic Electronics Engineering for SSC JE (Technical) | Test: Communication System- 1

Description

Attempt Test: Communication System- 1 | 25 questions in 50 minutes | Mock test for Electrical Engineering (EE) preparation | Free important questions MCQ to study Basic Electronics Engineering for SSC JE (Technical) for Electrical Engineering (EE) Exam | Download free PDF with solutions

QUESTION: 1

High-frequency waves are

A.
absorbed by the F₂ layer
B.
reflected by the D layer
C.
capable of use for long-distance communications on the moon
D.
affected by the solar cycle

Solution:

QUESTION: 2

Distance near the skip distance should be used for sky-wave propagation

A.
to avoid tilting
B.
to prevent sky-wave and upper ray interference
C.
to avoid the Faraday effect
D.
so as not to exceed the critical frequency

Solution:

QUESTION: 3

A ship- to-ship communications system is plagued by fading. The best solution seems to be the use of

A.
a more directional antenna
B.
a broadband antenna
C.
frequency diversity
D.
space diversity

Solution:

QUESTION: 4

In electromagnetic waves, polarization

A.
is caused by reflection
B.
is due to the tranverse nature of the waves
C.
results from the longitudinal nature of the waves
D.
is always vertical in an isotropic medium

Solution:

QUESTION: 5

As electromagnetic waves travel in free space, only one of the following can happen to them :

A.
absorption
B.
attenuation
C.
refraction
D.
reflection

Solution:

QUESTION: 6

Electromagnetic waves are refracted when they

A.
pass into a medium of different dielectric constant
B.
are polarized at right angles to the direction of propagation
C.
encounter a perfectly conducting surface
D.
pass through a small slot in a conducting plane

Solution:

QUESTION: 7

Diffraction of electromagnetic waves

A.
is caused by reflections from the ground
B.
arises only with spherical wave fronts
C.
will occur when the waves pass through a large slot
D.
may occur around the edge of a sharp obstacle

Solution:

QUESTION: 8

When microwave signals follow the curvature of the earth, this is known as

A.
the Faraday effect
B.
ducting
C.
tropospheric scatter
D.
ionospheric reflection

Solution:

QUESTION: 9

One of the following consists of no resonant antennas:

A.
The rhombic antenna
B.
The folded dipole
C.
The end-fire array
D.
The broadside array

Solution:

QUESTION: 10

Which one of the following terms does not apply to the Yagi-Uda array ?

A.
Good bandwidth
B.
Parasitic elements
C.
Folded dipole
D.
High gain

Solution:

QUESTION: 11

An antenna that is circularly polarized is the

A.
helical
B.
small circular loop
C.
parabolic reflector
D.
yagi-uda

Solution:

QUESTION: 12

Top loading is sometimes used with an antenna in order to increase its

A.
effective height
B.
bandwidth
C.
beam width
D.
input capacitance

Solution:

QUESTION: 13

Cassegrain feed is used with a parabolic reflector to

A.
increase the gain of the system
B.
increase the beamwidth of the system
C.
reduce the size of the main reflector
D.
allow the feed to be placed at a convenient point

Solution:

QUESTION: 14

A helical antenna is used for satellite tracking because of its

A.
circular polarization
B.
maneuverability
C.
broad bandwidth
D.
good front-to- back ratio

Solution:

QUESTION: 15

A helical antenna is used for satellite tracking because of its

A.
circular polarization
B.
maneuverability
C.
broad bandwidth
D.
good front-to-back ratio

Solution:

QUESTION: 16

When electromagnetic waves are propagated in a waveguide

A.
They travel along the broader walls of the guide
B.
they are reflected from the walls but do not travel along them
C.
they travel through the dielectric without touching the walls
D.
they travel along all four walls of the waveguide

Solution:

QUESTION: 17

The wavelength of a wave in a waveguide

A.
is greater than in free space
B.
depends only on the waveguide dimensions and the free-space wavelength
C.
is inversely proportional to the phase velocity
D.
is directly proportional to the group velocity

Solution:

QUESTION: 18

When a particular mode is excited in a waveguide, there appears an extra electric component, in the direction of propagation. The resulting mode is

A.
transverse-electric
B.
transverse-magnetic
C.
longitudinal
D.
transverse- electromagnetic

Solution:

QUESTION: 19

When electromagnetic waves are reflected at an angle from a wall, their wave-length along the wall is

A.
the same as in free space
B.
the same as the wavelength perpendicular to the wall
C.
shortened because of the Doppler effect
D.
greater than in the actual direction of propagation

Solution:

QUESTION: 20

As a result of reflections from a plane conducting wall, electromagnetic waves acquire an apparent velocity greater greater than the velocity of light in space. This is called the

A.
velocity of propagation
B.
normal velocity
C.
group velocity
D.
phase velocity

Solution:

QUESTION: 21

A signal propagated in a waveguide has a full wave of electric intensity change between the two further walls, and no component of the electric field in the direction of propagation. The mode is