Question 5
- Define antenna.
- State three elements of a satellite communication system.
- 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:
-
(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 2Wave
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.