Quiz on Telecommunications

Which one of these is NOT an example the use of telecommunications
1. Two children speaking to each other using a string telephone (two cans connected with a string)
2. A pilot receiving instructions from air traffic control.
3. Texting your friends on a mobile.
4. Recieving a new broadcast live by satellite.
Infra red signals are used to:
1. send smoke signals.
2. send messages to a satellite.
3. send digital pulses down a fibre optic cable.
4. give a sun tan.
A digital signal consists of:
1. A complicated wave.
2. Pulses of ON (1) and OFF (0)
3. Numbers
4. Numbers and letters
An advantage of using satellites is that:
1. it's cheap to send a satellite into space.
2. messages can be sent using ultra violet lasers.
3. satellites last for ever.
4. it avoids the need to lay lots of cables in cities, thereby causing disruption.
A geostationary satellite orbits the Earth every:
1. 1 hour
2. 24 hours
3. 1 week
4. 1 month