communications

Question 1

what are carrier waves

Answer 1

an electromagnetic wave that is modulated in amplitude or frequency to carry a signal.

Question 2

the shorter the radio wavelength

Answer 2

• the more information they can carry

-the shorter their range

-the less they spread out

Question 3

what is the job of radio waves less than 1 metre

Answer 3

used for tv broadcasting from tv masts because they can carry more information

Question 4

what is the job of radio waves from 1 metre to about 100m

Answer 4

used by local radio stations - because their range is limited to the area of the transmitter

Question 5

what is the job of radio waves greater than 100m

Answer 5

used by national and international radio stations because they have a much longer range than shorter wave length radio waves

Question 6

why is mobile phone radiation a bigger risk to children

Answer 6

because they have thinner skulls

Question 7

what are optical fibres used for

Answer 7

they are used to transmit signals carried by light or infrared radiation

-light rays cant escape form the fibre when they reach the surface of the fibre they are reflected back into the fibre.

Question 8

why are optical fibres better in comparison radio wave and microwaves

Answer 8

-optical fibres are more secure because the signals stay in the fibre

-optical fibres carry much more information as light has a much shorter wave length than radio waves and so can carry more pulses of waves.