Communications Flashcards Preview

GCSE Physics: Topic 13 > Communications > Flashcards

Flashcards in Communications Deck (11):

What are carrier waves?

Wves usd to carry any type of signal


What are radio and microwave spectrum divided into?

Different bands


Why are different bands used for different communication purposes?

Shorter the wavelength of the waves:

  • more information they carry
  • shorter their range
  • less they spread out


What are microwaves used for?

Satellite phone and TV signals - because they can travel between satellites in space and Earth


Why is it hard to say this is true?

Scientists think the radiation from mobile phones may affect brain , especially in children?

Further research is needed to evaulte this claim


Why are 

optical fibres carrying visible light / infrared radiation are useful in communications?

Because they carry much more information than radio wave and microwave transmissions


Why is light not better at communications than optical fibres?

As light has much shorter wavelength than radiowaves/ microwaves

more secure because waves stay in fibre


Instructions using radio waves

(radio station)

  1. Microphone produced audio signal - sound waves reach
  2. Radio waves are asborbed by reciever aerial
  3. Reciever circuit separates the audio signal from carrier waves
  4. Audio signal is supplied to loudspeaker , to emit sound waves



What is audio signal's function?

Used to modulate (vary the frequency) of carrier waves

Modulated carrier waves are supplied to transmitter aerial , emits radio waves and carry this signal


What happens when radio waves are absorbed by the reciever aerial?

Induce an alternating current , causes oscilliations in reciever

Same frequency of the radio waves