Question Papers For Board Examinations 2018

Class – XII

Subject – Peration And Maintenance of Communication Devices

Subject : Peration And Maintenance of Communication Devices

Class : XII

Year : 2018

General Instructions :

Attempt any thirteen questions. Each question carries one mark. Select the correct answer. 

Questions :

SECTION A

1.Which medium is/are used in a communication system ?
(1) Fibre optic
(2) Atmosphere
(3) Coaxial cable
(4) All of the above 

2.If the frequency range of an electronic signal is high, what will be its bandwidth ?
(1) High
(2) Low
(3) Medium
(4) No relation 

3.Through which medium does ‘space wave’ propagation take place ?
(1) Ionosphere
(2) Troposphere
(3) Over the surface of the Earth
(4) Waveguide 

4.In a Cellular Radio System, if the cell size is increased, the transmitter power will be
(1) Decreased
(2) Increased
(3) No change
(4) Exponentially decreased 

5.In a satellite, how much is the intensity of downlink signals in comparison to uplink received signals ?
(1) No relation
(2) Very high
(3) Very low
(4) Equal 

6.The ‘Elevation’ of a satellite is that angle which the satellite makes
(1) With the horizon
(2) Clockwise from North
(3) Clockwise from South
(4) With the equator 

7.In a satellite, for transmission and reception of main signals, how many antennas are there ?
(1) One (common for both)
(2) Two (separate for each)
(3) One or two (depends on satellite)
(4) Three 

8.With reference to mobile phones, what is the full form of UIM ?
(1) User Interface Multiplexing
(2) User Interface Module
(3) Unique Identity Module
(4) User Identity Module

9.What is the frequency range on which mobile phones operate ?
(1) 300 MHz to 3000 MHz
(2) 825 MHz to 890 MHz
(3) 3 MHz to 30 MHz
(4) 100 MHz to 1000 MHz

10.What is the shape of ‘cells’ in a Base Master System ?
(1) Circular
(2) Hexagonal
(3) Square
(4) Triangular

11.The components are soldered and desoldered on a PCB, by an SMD Rework Station through
(1) Hot Air
(2) Direct Heating
(3) Dielectric Heating
(4) None of the above

12.For voice signals, what type of modulation is used in a mobile phone ?
(1) Amplitude Modulation
(2) Frequency Modulation
(3) Phase Modulation
(4) None of the above 

13.The radiating power of a mobile phone
(1) remains constant
(2) changes like a sine wave
(3) changes with time
(4) is controlled by a microprocessor 

14.Which is the first device (equipment) best suited to repair a wet mobile phone ?
(1) Multimeter
(2) CRO
(3) Hot air gun
(4) Soldering station

15.To become a successful mobile repair technician, the ‘Technical Support Guidance’ can be obtained from
(1) Internet
(2) Training Institutes
(3) Books
(4) All of the above   

Click Here To Download Full Paper

<< Go Back To Main Page

Courtesy: CBSE