Communications Flashcards Preview

GCSE Physics: Topic 13 > Communications > Flashcards

Flashcards in Communications Deck (11):
1

What are carrier waves?

Wves usd to carry any type of signal

2

What are radio and microwave spectrum divided into?

Different bands

3

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

4

What are microwaves used for?

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

5

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

6

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

7

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

8

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

9

10

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

11

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