light and the electromagnetic spectrum Flashcards

1
Q

what does the angle of incidence =

A

angle of reflection

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what is the angle of incidence

A

the angle between the incoming wave and the normal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what is the angle of reflection

A

the angle between the reflected wave and the normal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

what is the normal and how is it usually shown

A

shown through a dotted line

it’s a imaginary line that’s perpendicular to the surface at the point of incidence

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

what does total internal reflection depend on

A

critical angle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

what is specular reflection

A

when waves are reflected in a single direction by a smooth surface, means you get a clear reflection

e.g. when light reflects by a mirror

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

what is diffuse reflection

A

when waves are reflected by a rough surface and the waves are reflected in all directions
e.g. paper

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

how to investigate refraction using a glass block

A

1) place a rectangular glass block on a piece of paper and trace around it. Use a ray box to shine a ray of light at the middle of one side of the block.

2) Trace the incident ray and the emergent ray on the other side of the block. Remove the block and, with a straight line, join up the incident ray and the emergent ray to show the path of the refracted ray through the block.

3) Draw the normal at the point where the light ray entered the block. Use a protractor to measure the angle between the incident ray and the normal (the angle of incidence, I) and the angle between the refracted ray and the normal (the angle of refraction, R).

4) Do the same for the point where the ray emerges from the block.

5) Repeat this three times, keeping the angle of incidence as the ray enters the block the same.

6) Calculate an average for each of the angles.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

what do colour and transparency depend on

A

absorbed wavelengths

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

colour

A

differences in absorption, transmission, and reflection of different wavelengths by different materials

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what is white light a mix of

A

all the the different colours of light, all different wavelengths

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

objects which reflect all of the wavelengths of the visible light equally

A

white

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

objects which absorb all wavelengths of visible light

A

black

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

objects which transmit light

A

transparent (see through)
translucent (partially see through)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

objects which do not transmit light

A

opaque objects

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

colours with long wavelengths and low frequency

A

reds, oranges, yellows and partially green

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

colours with short wavelengths and high frequencies

A

purple, blue into greens

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

what are the 2 main types of lens

A

converging
diverging

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

what is a converging lens

A

lens which bulges outwards on the middle, causes parallel rays of light to be brought together
also know as convex lens

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

what is a diverging lens

A

a lens which caves inwards, causes parallel rays of light to spread out

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

what is the principle focus of
converging lens

A

where rays hitting the lens parallel to the axis all meet

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

what is the principle focus of a diverging lens

A

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

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

what is the focal length

A

the distance from the centre of the lens to the principle focus

24
Q

which lens is the power positive

A

converging lens

25
which lens is the power negative
diverging lens
26
what does the power of the lens increase with
curvature
27
draw a ray diagram for an image through a diverging lens
1) Pick a point on the top of the object. Draw a ray going from the object to the lens parallel to the axis of the lens. 2) Draw another ray from the top of the object going right through the middle of the lens. 3) The incident ray that's parallel to the axis is refracted so it appears to have come from the principal focus (F). Draw a ray from the principal focus. Make it dotted before it reaches the lens (as it's virtual here). 4) The ray passing through the middle of the lens doesn't bend, 5) Mark where this ray meets the virtual ray. That's the top of the image. 6) Repeat the process for a point on the bottom of the object. When the bottom of the object is on the axis, the bottom of the image is also on the axis.
28
how to draw a ray diagram for an image through a converging lens
1) Pick a point on the top of the object. Draw a ray going from the object to the lens parallel to the axis of the lens. 2) Draw another ray from the top of the object going right through the middle of the lens. 3) The incident ray that's parallel to the axis is refracted through the principal focus (F). Draw a refracted ray passing through F. 4) The ray passing through the middle of the lens doesn't bend. 5) Mark where the rays meet. That's the top of the image. 6) Repeat the process for a point on the bottom of the object. When the bottom of the object is on the axis, the bottom of the image is also on the axis.
29
what type of wave are electromagnetic waves
transverse
30
what speed to electromagnetic waves travel
all the same in a vacuum (space) different speeds in different materials
31
what is electromagnetic waves wavelength
from 10 -15m to more than 10 (4) m
32
how do you group EM waves
by wavelength and frequency
33
what are the 7 types of waves
radio micro infrared visible light ultra violet x-rays gamma rays
34
which waves have the longest wavelength and low frequency
radio micro infrared (visible sits in the middle)
35
which waves have the shortest wavelength and high frequency
gamma x rays ultra violet (visible sits in the middle)
36
radio waves properties
transmitted through the body without be absorbed
37
microwaves properties
can be absorbed causing heating of cells
38
infrared and visible light properties
reflected and absorbed burns skin if it gets too hot
39
ultraviolet properties
a type of ionising radiation also absorbed by the skin but at a higher frequency causes damage to cells - skin cancer damage to eyes (blindness)
40
x-rays and gamma rays properties
ionising - can cause mutations and damage cells higher frequencies transfers energy absorbed by deeper tissue
41
what does every object absorb and emit
EM radiation
42
what’s the best emitter out of black and white surfaces
black
43
what does radiation effect and why
the earths temperature as it depends on the amount of radiation it reflects, absorbs and emits
44
what can cause a change to the earths overall temperature
changes to the atmosphere
45
what is radiation like during the day
lots of it, some is reflected most is absorbed increasing the temp
46
what is radiation like during the night
radiation is emitted by the atmosphere, clouds and the earths surface decreasing the temp
47
what are EM waves made up of
oscillating electric and magnetic fields
48
what are radio waves made up of
oscillating charges
49
how can you produce radio waves
using alternate current in an electrical circuit. the object charges electrons oscillate to create the radio waves called a transmitter
50
what are radio waves used for
communication and broadcasting e.g. bluetooth, TV and FM radio
51
what are microwaves and radio waves used by
satellites e.g. tv signals and satellite phones
52
what are microwaves used for
can be used for satellites heating food
53
what is infrared radiation used for
increase or monitor temperature e.g. infrared cameras thermal imaging infrared sensors, security systems transfer information
54
what is visible light used for
photography - digital cameras and photographic film seeing in general
55
what is ultraviolet used for
fluorescent lamps security pens sterilise water
56
what are x-rays used for
seeing inside of things e.g. hospital photos to check broken bones airport security scanners
57
what are gamma rays used for
sterilise medical instruments and food - kill microbes cancer treatment, can treat but can cause more damage to healthy cells too