Radio,Television And Electronic Paper 2, WASSCE (SC), 2017

Question 5

 

  1. Define antenna.
  2. State three elements of a satellite communication system.
  3. Some applications of the electromagnetic waves listed in Table 2 are as follows:

kills mutated cells                                                detect bone fracture
electronic communication                                    remote sensing
synthesis of vitamin D in skin

Complete Table 2 with the appropriate application.
Table 2

 

Wave

Application

i

Radio wave

 

ii

Infrared radiation

 

iii

Ultraviolet

 

iv

X-ray

 

v

Gamma rays

 

 

 

Observation

  The expected answers were:

  1. (a) Definition of antenna

    • An antenna is a device/conductor that converts electric power into radio waves and vice versa.
    • A device that transmits and receives signals such as microwave, radio and satellite signals.
    • A device that converts electromagnetic radiation in space into electrical current in conductors and vice versa.                                                                            

    (b) Elements of satellite communication system

    • Satellite orbit
    • Link
    • Earth station
    • Transponders
    • Receiver
    • Transmitter    



    (c)                                                    Table 2

     

    Wave

    Application

    I

    Radio wave

    For electronic communication

    II

    Infrared radiation

    For remote controls

    III

    Ultraviolet

    Synthesis of vitamin D in skin

    IV

    X-rays

    Detect bone fracture

    V

    Gamma rays

    Kills mutated cells

     
    Majority of the candidates that attempted the this question responded well, especially the (c) part.