TELECOM Communication Using Cables

Question 0

Coded messages are sent from a _____ and picked up by a _______

Answer 0

Transmitter, receiver

Question 1

Give a method of sending a message using code

Answer 1

Morse code

Question 2

Give an example of range communication

Answer 2

Telephone

Question 3

Give the energy changes that occur Ian telephone

Answer 3

Sound to electrical and electrical to sound

Question 4

The transmitter in a telephone is

Answer 4

The microphone

Question 5

The receiver in a telephone is

Answer 5

The loudspeaker

Question 6

What are electrical signals transferred through when using telephone communication?

Answer 6

Wires

Question 7

What speed to electrical signals travel through wires at?

Answer 7

3x10*8

Question 8

What happens to the amplitude of louder sounds? Why?

Answer 8

Louder notes have more energy than quiet notes so have a larger amlplitude

Question 9

What happens to the frequency of sound waves? Why?

Answer 9

High pitch noise produces more waves per second than low pitch so have a higher frequency

Question 10

What is an optical fibre?

Answer 10

A long thin thread of glass through which light can travel

Question 11

Can light be reflected?

Answer 11

Yes

Question 12

State the law of reflection

Answer 12

When light is reflected the angle of incidence is equal to the angle of reflection

Question 13

How do electrical signals vary with frequency and loudness

Answer 13

The same as sound waves

Question 14

Give advantages of optical fibres

Answer 14

Smaller, cheaper, lighter, more info transmitted, higher signal quality, less repeaters necessary.

Question 15

At what speed do signals travel in optical fibres?

Answer 15

2x10*8

Question 16

Give an advantage of electrical cables

Answer 16

Easier to join together than optical finres

Question 17

If a a ray of light is reversed what path will it follow?

Answer 17

The same in the opposite direction

Question 18

Why do optical fibres work?

Answer 18

Total internal reflection

Question 19

When does total internal reflection occur?

Answer 19

When the incident ray is greater than the critical angle

Question 20

What is the critical angle for glass?

Answer 20

42

Question 21

Why is an optical fibre less likely to be interfered with?

Answer 21

It is not electrical so cannot be interrupted by electrical interference

Question 22

Why are optical fibres cheaper?

Answer 22

Glass is cheaper than copper

Question 23

How often do electrical wires need boosted?

Answer 23

Every 4km

Question 24

Does any light leave optical fibres?

Answer 24

No it is all reflected inside