3.2 Reflection

Question 0

What is the incident ray?

Answer 0

The ray coming in.

Question 1

What can be reflected?

Answer 1

light

Question 2

What is the normal?

Answer 2

A dotted line perpendicular to the boundary that the wave is to meet.

Question 3

What is the angle of incidence?

Answer 3

The angle measured from the normal to the incident ray

Question 4

What is the angle of reflection?

Answer 4

The angle measured from the normal to the reflected ray

Question 5

What is the symbol for the angle of incidence?

Answer 5

i

Question 6

What is the symbol for the angle of reflection?

Answer 6

r

Question 7

What happens if the direction of the incident ray is reversed?

Answer 7

The ray will follow the same path.

Question 8

What is the relationship between the angle of incidence and reflection?

Answer 8

they are equal

i=r

Question 9

In curved reflectors what is the focus? (2)

Answer 9

• The point at which all reflected waves meet

- Large resultant amplitude

Question 10

What happens if transmitter is placed at focus?

Answer 10

Curved reflector reflects the incident waves so they merge in parallel formation.

Question 11

What happens if a receiver is placed at focus?

Answer 11

The curved reflector reflects the parallel formed incident waves to a point , the focus.

Question 12

Describe an application do curved reflectors in telecommunications?

Answer 12

on a satellite dish the curved reflector reflects waves to a focus where a receiver is placed meaning the best signal is received.
curved dish transmitter used to send strong signal to satellites in orbit which amplify the signal and use curved reflectors to send it back to earth.

Question 13

What is the critical angle? (2)

Answer 13

• angle of incidence that produces an angle f refraction 90degrees
• maximum angle of incidence at which refraction occurs

Question 14

Is the value of the critical angle a specific number for every medium?

Answer 14

The value is specific to each individual medium

Question 15

What is total internal reflection?

Answer 15

Occurs when the angle of incidence of a ray is greater than the critical angle for the medium it is travelling through.
This means the ray does not leave the medium but it reflected at the boundary instead.
i>c means i=r

Question 16

How does an optical fibre work?

Answer 16

The incident rays meet the edge of the fibre(high quality glass) at an angle greater than the critical angle for glass meaning they are reflected back into the fibre.
This continues and the ray travels up the fibre.

Question 17

Describe a use for optical fibres and two advantages of this…

Answer 17

transmission of computer data and telephone calls

• carry more data than cables of the same width
• signal does not weaken as much as cables so good for long distance