Electromagnetic waves used in communication

Question 1

How can some frequencies of radiation be used for transmitting information?

Answer 1

Some radio waves and microwaves are not strongly absorbed by the atmosphere so can be used for TV and radio,
Light and infrared can travel long distances through glass without being significantly absorbed so can be used along optical fibres

Question 2

What are the two kinds of signal?

Answer 2

There is analogue and digital, analogue is a signal that can continuously vary from 0 to 1, digital is a signal that uses only 0 or 1 to represent information

Question 3

What advantages are there of digital over analogue?

Answer 3

If the signal is interrupted by noise, in digital it can easily be recovered as its obvious whether it was either on or off, whereas analogue could be any decimal from 0 to 1

Question 4

How can sound and images be sent and received using binary?

Answer 4

The data can be represented by short bursts of either on (1) or off (0) and then when received can be decoded back into the original data form

Question 5

How can quality of sound or image be improved?

Answer 5

The more information stored the higher quality the sound or image would be, binary can also be stored and processed by computers to reduce risk of human error in coding and decoding