P14

Question 1

What can all waves be?

Answer 1

Absorbed,transmitted or reflected

Question 2

When a wave arrives at a boundary between two different materials what happens?

Answer 2

• The waves are absorbed by the material the wave is trying to cross into this transferes the energy to the material energy stores
• The waves are transmitted. Refraction happens
• The waves are reflected

Question 3

Angle of incidence =

Answer 3

Angle of reflection

Question 4

Whats the angle of incidence?

Answer 4

The angle between the incoming line and normal

Question 5

Whats the angle of reflection?

Answer 5

The angle between the reflected and the normal

Question 6

Whats the normal line?

Answer 6

An imaginary line perpindicular to the surface at the point of incidence. Normally the dotted line

Question 7

When does specular reflection happen?

Answer 7

A wave is reflected in a single direction by a smooth surface.

Question 8

Give an example of specular reflection?

Answer 8

When light is reflected in the mirror and you get a clear reflection

Question 9

What is diffuse reflection?

Answer 9

When a wave is reflected by a rough surface and the rays are scattered in different directions

Question 10

What happenes when loght is reflected by a rough surface?

Answer 10

The surface appears matte and you don’t get a clear reflection of objects

Question 11

What’s refraction?

Answer 11

Waves changing direction at a boundary

Question 12

What happens when a wave crosses a boundary at an angle and changes direction?

Answer 12

It refracts

Question 13

What does how much it refracts depend on?

Answer 13

• How much it speeds up or slows down
• Also density of 2 materials

Question 14

What does a higher density mean?

Answer 14

It will slow down

Question 15

What happens when a wave crosses a boundary and slows down?

Answer 15

It will bend towards the normal line

Question 16

What happens if it crosses into another material and speeds up?

Answer 16

Bend away from the normal line

Question 17

What happens when the wavelength of a wave stays the same?

Answer 17

The frequency stays the same

Question 18

What happens if a wave travels across the normal line?

Answer 18

Change speed but not refract

Question 19

Why do waves go in a different direction?

Answer 19

The wave hit a medium

Question 20

Whats the optical density?

Answer 20

A measure of How quickly light can travel through it

Question 21

What does higher the optical density mean?

Answer 21

The slower light waves travel through it

Question 22

Why should you do the practical in a dim room?

Answer 22

So you can see the light rays better

Question 23

What materials can you use to investigate refraction?

Answer 23

Transparent

Question 24

What are the steps for the transparent material?

Answer 24

1) Place a transparent block on a peice of paper and trace around it. And shine a ray box at the block
2) trace the incident ray and mark the emerging ray. Then draw a straight line to each other to show the refracted ray
3) draw the normal when the light enetered the block, use a protractor to measure between the normal and refracted.
4) Repeat using rectangle blocks with different materials keeping the incident ray the same.

Angle of refraction change for different materials

Question 25

How do lenses form images?

Answer 25

By refracting light and chnaging it's direction

Question 26

Whats a convex lens?

Answer 26

Bulges outwards and causes rays of light parallel to the axis to be brought together at the focus point.

Question 27

Whats a concave lens?

Answer 27

Caves inwards and causes parallel rays of light to spread out

Question 28

Whats the axis of a lens?

Answer 28

The line passing through the middle of the lens

Question 29

Whats the principle focus of a convex lens?

Answer 29

Is where rays hitting the lens parallel to the axis all meet

Question 30

Whats the principle focus of a concave lens?

Answer 30

The point where rays hitting the lens parallel to the axis appear to all come from.

Question 31

Whats the focal length?

Answer 31

The distance from the centre of the lens to principle focus

Question 32

What are the 3 rules for refraction in convex lens?

Answer 32

- an incident ray parallel to the axis refracts through the lens and passes through the principal focus on the other side. - an incident ray passing through the principal focus refracts through the lens and travels parallel to the axis - an incident ray passing through the centre carrys on

Question 33

Rules for concave lens?

Answer 33

- An incident ray passing through the centre of the lens carrys on in same direction - An incident ray passing towards the principal focus refracts through the lens and is parallel to the axis - An incident ray parallel to the axis refracts through the lens and travels in line with the prinicpal focus

Question 34

What can lenses produce?

Answer 34

Real and virtual images

Question 35

What is a real image?

Answer 35

When the light from an object comes together to form an image on the screen like the image formed on the eyes retina

Question 36

Whats a virtual image?

Answer 36

Is when rays are diverging so the light from the object appears to come from a different place

Question 37

An example of a virtual image?

Answer 37

When you look in the mirror because the objects behind the mirror

Question 38

What are the 3 things to describe an image?

Answer 38

- How big is it - Real or virtual - Upright or inverted

Question 39

What lens always creates virtual images?

Answer 39

Concave lens

Question 40

What uses convex lenses?

Answer 40

Magnifying glasses

Question 41

Magnification =

Answer 41

Image height/object height

Question 42

What is visible light made from?

Answer 42

A range of colours

Question 43

What does each colour have?

Answer 43

Own range of wavelengths and frequencies

Question 44

How do you make other colours?

Answer 44

By mixing them

Question 45

What are the ony colours you can get without mixing?

Answer 45

Red,green,blue

Question 46

What do all different colours create?

Answer 46

White light

Question 47

What do colour and transparency depend on?

Answer 47

Absorbed wavelengths

Question 48

What happens when visible light hits an opaque objects?

Answer 48

They absorb some wavelength and reflect others

Question 49

What does the colour of an opaque object depend on?

Answer 49

Which wavelengths are strongly reflected

Question 50

What happens to opaque object that aren't a primary colour?

Answer 50

They reflect on other wavelengths of light corrosponding to that colour

Question 51

What do white objects reflect.

Answer 51

All visible light equally

Question 52

What do black objects absorb?

Answer 52

All wavelengths of visible light

Question 53

What are colour filters used for?

Answer 53

Filter out different wavelenths of light so that only certain colours are transmitted

Question 54

What does a primary colour transmit?

Answer 54

Only that colour

Question 55

What happens when a different colour goes through a colour filter ?

Answer 55

Goes black