Optic Fibre & Communication

Question 1

What are optic fibres used for ?

Answer 1

To carry signals in the form of pulses of light or other parts of EM spectrum

Question 2

What speed do electromagnetic waves travel in a vacuum ?

Answer 2

Same speed in a vacuum

Question 3

What is the speed of light ?

Answer 3

3.00 x 10(8) ms-1

Question 4

What is Refraction ?

Answer 4

Bending of light , describe the light ray after it has change direction

Question 5

What is the incidence ?

Answer 5

The incoming light ray

Question 6

What does internal reflection refer to ?

Answer 6

When a wave in a optically dense medium hit a Boundry with an optically less dense medium so energy is reflected back onto denser medium

Question 7

What does critical angle refer to ?

Answer 7

the angle of incidence beyond which rays of light passing through a denser medium to the surface of a less dense medium are no longer refracted but totally reflected.

Question 8

What is total internal reflection ?

Answer 8

All of the wave energy if you selected back into the more dense medium

Question 9

What waves are in the electromagnetic spectrum?

Answer 9

Radio waves 
Microwaves 
Inferred 
Radiation 
Visible light 
Ultra violet 
X-rays 
Gamma rays

Question 10

What wave has the highest frequency and lowest ?

Answer 10

Gamma - highest

Radio wave - lowest

Question 11

What waves have the longest and shortest wavelength ?

Answer 11

Gamma ray - shortest

Radio wave - longest

Question 12

What are features of Bluetooth ?

Answer 12

• can go through walls
• short distance (10m)
• radio waves
• connects devices

Question 13

What is the role of cladding ?

Answer 13

-Reduces energy loss as fewer
reflections happen
-protects the core from damage

Question 14

What is the core ?

Answer 14

Part of the fibre that guides light

Question 15

What are features of broadband ?

Answer 15

• used light in optic fibres = faster

- uses multiplex signals (many at one time

Question 16

Which EM wave is used for sending Bluetooth signals ?

Answer 16

Radio waves

Question 17

Where must a satellite be in order to use radio waves for sate light communication ?

Answer 17

Below the ionosphere

Question 18

What is a fibre optic made of ?

Answer 18

A very long, thin and flexible cylinder of glass or plastic

Question 19

Features of microwaves

Answer 19

• can pass through the ionosphere
• better quality and clearer communication
• little to no interference

Question 20

Disadvantages of microwaves

Answer 20

• can only be used in the line of sight
• transmission is affected by wet weather
• cannot communicate through water

Question 21

Advantages of radio waves

Answer 21

• can reflect off the ionosphere
• can reach receivers out of site of the transmitter
• can be transmitted underwater

Question 22

Disadvantage of radio waves

Answer 22

• cannot carry as much information

- subject to interference