Physics - Properties of Light Flashcards
(239 cards)
1
Q
Waves definition
A
Waves are motions which carry energy from one place to another
2
Q
What are the two types of waves?
A
Transverse and Longitudinal waves
3
Q
Transverse waves and examples
A
the vibrations are at right angles to the direction of travel
eg. X-rays, microwaves, radio waves, Seismic waves
4
Q
Longitudinal waves and examples
A
the vibrations are in the same direction as the direction of travel
eg. Sound waves, spring waves, A vibrating drumhead
5
Q
Can waves travel in all 3 dimensions?
A
Yes
6
Q
1 dimension wave travelling example
A
A longitudinal or transverse wave travelling along a rope. The rope confines the energy to the rope
7
Q
2 dimension wave travelling example
A
A transverse wave travelling from a point source of disturbance in still water – a pebble in a pond
8
Q
3 dimension wave travelling example
A
Sound waves travel immediately away from the source in 3-dimentions with a spherical wave front. A source of light will illuminate a 3-dimentional space
9
Q
The wave model - Initial level
A
The line that is positioned at roughly the middle of the crest and trough
10
Q
The wave model - Amplitude
A
The space between the crest and the mean position (the middle line between the crest or trough)
11
Q
The wave model - Crest
A
Where the displacement of the medium is at the maximum (when the movement of the medium from it’s initial position [which was before the wave travelled through it], was at the maximum)
12
Q
The wave model - Trough
A
The lowest point from the mean position in a wavelength
13
Q
The wave model - One wavelength
A
Trough to trough or crest to crest
14
Q
Amplitude definition
A
The distance between the maximum height of displacement of the medium from its equilibrium position (the undisturbed state of the medium), and is usually measured in meters.
(For transverse waves the amplitude is half the distance between the crest and trough)
15
Q
Wavelength in transverse waves vs longitudinal waves
A
Transverse waves - The wavelength is the distance between 2 continuous crests or two troughs
Longitudinal waves - The wavelength is the distance between two adjacent zones of compression or rarefaction
16
Q
Rarefaction
A
When the frequency of the waves is low in longitudinal waves
17
Q
Compression
A
When the frequency of the waves is high in longitudinal waves
18
Q
Frequency (f) and the units used with it
A
The number of waves produced by a source or number of complete cycles (the up and down pattern) each second
The unit used if often Hertz (hz) per second however kilohertz (kHz), megahertz (MHz) and gigahertz (GHz) can be used if the frequency is very high
19
Q
Period (T)
A
The time in seconds for one complete cycle (the up and down pattern)
20
Q
Equation for period (T)
A
T = 1/f
21
Q
Equation for frequency (f)
A
F = 1/T
22
Q
Phase
A
If two points on a wave are in phase, at a particular instant in time, they have the same displacement and same velocity
(Imagine drawing a set of waves and then another set of waves directly on top of it and on the same line [a line over a line})
23
Q
Equation for velocity
A
V = change in displacement/change in time
V = (triangle) s / (triangle) t
24
Q
Wave speed/velocity and what unit is used
A
Wave speed (metres per second) = Frequency (Hertz) x Wavelength (Metre/s)
V = f x λ
The answer is in metres per second (m/s)
25
What is the symbol 'λ' and what does it show
The symbol's name is 'lambda' and it shows the wavelength of any wave
26
Difference between sound and light waves
Sound waves are mechanical waves meaning they need a medium to move
Light waves are electromagnetic waves and do not need a medium to travel which is how the sun and stars can reach us in Earth
27
Types of electromagnetic waves (from lowest frequency to highest frequency)
Radio waves
Micro waves
Infrared waves
Visible radiation (visible light)
Ultraviolet waves
X-rays
Gamma waves
28
Radio waves purpose/examples
Communication, Tv, phone, medicine
29
Micro waves purpose/examples
Type of radio waves used in cooking and cell phone communication
30
Infrared waves purpose/examples
Military, Police, Medicine, Heat detection
31
Visible Radiation (Visible light) purpose/examples
Allows the human perception of objects (allows us to see things and see them with colour)
32
Ultraviolet waves purpose/examples
Enables skin cells to produce vitamin D, kills bacteria, can cause skin and eye damage if exposed
33
X-Rays purpose/example
Medicine
34
Gamma Waves
Cancer treatment (killing the cells)
35
The more higher the frequency of a wave...
the more dangerous/strong it can be
36
What is radio waves good for?
Transmitting signals over long distances as they have the longest wavelength
37
What is the frequency of radio waves?
10^3 to 10^9 hertz
38
What does EMS stand for?
Electromagnetic Spectrum
39
What is AM and FM radio
When we turn on radio we turn on AM or FM radio
40
Microwaves are radio waves...
with the shortest wavelength
41
Why are Microwaves used in cell phone communication?
This is as they do not get easily blocked by trees, mountains, etc...
42
What type of objects give of Infrared radiation?
Any hot objects
43
What is visible light made up of?
The colours of the rainbow is how we see them
44
Gamma rays have the most ... and the highest ...
Energy
Frequency
45
In what shape does light travel? (Bent line, straight line, curved line, etc...)
Straight line
46
How do we see objects that don't even emit light?
The light is reflected
47
What kind of wave is a surface ocean wave? (transverse or longitudinal)
Waves on the surface of the ocean are transverse waves since the water is moving up and down and therefore at 90° to the direction the wave travels
48
Opaque
Does not allow light to pass through
All light is either absorbed or reflected
49
Translucent
Can be seen through, but not clearly
Allows some light to go through, but some is also absorbed or reflected
50
Transparent
Allows almost all light to go through, so can be seen through clearly
51
What colour is made up of all the colours of the rainbow?
White
52
White light
Reflects all light and absorbs none
53
Black light
Absorbs all light and reflects none
54
Three secondary colours of light
red + blue = magenta
blue + green = cyan
red + green = yellow
and the equations
55
Three primary colours of light
green
red
blue
56
What type of waves are light waves? (transverse or longitudinal)
Transverse
57
Absorption
The transfer of light energy into an object where it is transferred into heat energy (the object gets hotter)
58
Transmission
When light passes through an object without being absorbed or reflected
59
Normal
The “normal” is a line perpendicular (at 90° degrees) to a surface
60
Incident ray
The ray of light before it reaches a surface
61
Reflected ray
The ray of light that has reflected and bounced of off a surface
62
Angle of incidence
The angle between incident ray and normal line
63
Angle of reflection
The angle between reflected ray and normal line
64
Law of reflection
If the ray is reflected on a smooth surface then the angle of incidence and the angle of reflection will be the same degrees
65
Diffuse reflection
When light (a light ray) is reflected off of a uneven or rough surface and is reflected in different directions
66
Pulse
A singular wavelength or less (maybe half a wavelength [only the up or down curve])
67
Periodic/Continuous waves
Waves that keep on going in a pattern constantly
68
Photon
A particle of light
69
Reflection
When light rays are bounced off of an object as a reflected ray
No light is absorbed or transmitted
70
Where is the normal located
At 90 degrees to the contact point
If at flat surface then normal would be a straight line in the middle however if on a rough/angled surface then it would be a straight line on an angle exactly where contact was made
71
Refraction
When a light ray hits a surface, it will change speed and direction
For example, a straw in a bottle
72
Does colour change in a light ray when a light ray goes through an object?
No
73
Medium boundary
A surface
74
Critical angle
the angle above which total internal reflection occurs
When a light ray hits water from air and it turns/reflects 90 degrees as the angle of incidence is larger than the refraction one
75
Media
Multiple mediums
76
Refractive index (n)
A ratio of speed of light in a vacuum compared to light in that medium (in simple words it describes how much a light ray changes/bends from one medium to another)
77
Vacuum
A place where matter does not exist and there is no medium
For example, space does not stop light and has not matter/media
78
Total internal reflection
The reflection of all incident light at a boundary between two media
79
Refractive index equation
n = c/v
c = speed of light in a vacuum which is 300,000,000 m/s (3 times 10^8)
v = speed of light in the medium
n = refractive index
IF NEEDED TO FIND V THEN REARRANGE THE EQUATION TO MAKE V THE SUBJECT
80
Speed of light in a vacuum
3 x 10^8 (300,000,000) m/s
You SUBSTITUTE this into the refractive index equation (n= c/v)
81
What happens to light if the medium is dense
The more dense a medium is the more the light bends towards the normal
82
Symbols for angle of incidence and reflection
Incidence = Qi (the I goes on the bottom)
Reflection = Qr (the r goes on the bottom)
83
Snell's Law (all letters are on the bottom of the symbol next to it)
Ni Sin (theita i) = Nr Sin (theita r)
The angles of incidence and reflection go in the brackets, and the refractive index (n) goes outside. This law REQUIRES A CALCULATOR
You need inverse operations for this
This equation can be used to find the refractive index of the incidence and reflected ray
84
The bigger the 'n' value (refractive index) the....
slower light travels
85
How to determine when n is smaller or larger in refraction
If going from a less dense medium (ni is smaller) to a more dense medium (ni is larger) the ray will bend towards the normal. If the ray is bending away from the medium then it is the opposite (ni is larger then nr)
86
Does the frequency of a wavelength ever change when going medium to medium?
No why would it change u bum
87
When should numbers be rounded when calculating
You can round numbers when writing them mid equation so you don't have to write it all but you must not round it in your calculations
88
What does Sin give us?
The sin gives us the opposite side over the hypotenuse
You would put 'sin(whatever the angle is to the side of the right angle)'. This would give
89
What does sin-1 give us?
We use this when we know the opposite side and the hypotenuse yet we need to know the angle next to the right angle (the feitha angle)
We do 'sin(opposite over hypotenuse)'
90
What happens when a critical angle occurs? Does the angle still refract?
A critical angle occurs from a dense medium to a less dense medium. The refracted ray bends exactly on the surface (90 degrees). The refracted index instead reflects off of the surface and applies the law of reflection. The refractive angle becomes the reflection angle.
91
Refractive angle
The angle that forms after the incident ray refracts
92
Total internal reflection
When the refractive ray is at 90 degrees and reflects. It happens when the ANGLE OF INCIDENCE IS LARGER THAN THE ANGLE OF REFRACTION (which forms a critical angle)
(It is why we can see reflections in water, however the bigger the angle the better it reflects, which is why when we look down in water from height there is less of a reflection as the angle is smaller but when we look further away in the water, there is more of a reflection as there is a larger angle)
93
Refractive ray
When the incident ray bends in a medium
94
If the incident angle is larger than the critical angle, can light bounce in curvy objects
Yes as total internal reflection will just reflect the light back above the surface like a normal reflection (eg. light shone in a curved pipe)
95
What is the equation to find the critical angle
Theita c = Sin -1 (nr/ni)
the nr and ni is the refractive index of the refractive and incident mediums (media)
96
When do you use Snell's law?
When it is a refractive angle question
97
What is the refractive index in air
1
98
What is the refractive index in water
1.33
99
Apparent depht
When looking into water for example, if u see a fish it looks shallower and further away than it actually is, however because of the refraction the light bends (refraction) and the fish is actually deeper in the water and closer to you. The fish is at the end of the refractive ray, however it looks differently
100
What happens if a light ray goes through a medium with a less refractive index compared to more?
If a light ray goes through a medium with a less refractive index, it moves away from the normal
If a light ray goes through a medium with a bigger refractive index, it move towards the normal
101
The bigger 'n' is in the refractive index equation, the ......... and the smaller 'n' is the ...........
The bigger 'n' is in the refractive index equation, the smaller the speed of light is
The smaller 'n' is the faster the speed of light is
102
Dispersion
Splitting of light into it's various colours
103
What colour bends more when changing medium?
A blue light bends more when changing medium
104
What colour bends less when changing medium?
Red bends less when changing medium
(meaning the ray will be more like the incident ray before it hit another medium as it won't bend much)
105
Scientific term for Rainbow
Full spectrum
106
What are the prime colours when mixing light?
Red, green and blue
107
Why do certain colours bend differently in light?
This is as different colours have a different refractive index (n)
108
What do you get from combining all three primary light colours
White light
109
Speed equation
d/t
110
What is special about mechanical waves?
They require a medium to pass through eg. sound waves
111
Wavelength equation (lambda)
Wavelength (lambda) = wave speed/velocity (v)/frequency (f)
112
What is radioactivity?
The process of unstable nucleus emitting particles
113
Why does a nucleus undergo radioactivity?
It wants to become stable
114
What do nuclear reactions involve?
Interactions between the nuclei of atoms
115
What is the principle of matter and energy?
They cannot be created nor destroyed
116
How are matter and energy related?
They are two forms of the same thing
117
What does Einstein's formula E = mc² represent?
Energy equals mass times the speed of light squared
118
What does E represent in Einstein's equation?
Energy
119
What does m represent in Einstein's equation?
Mass
120
What does c represent in Einstein's equation?
Speed of light (Universal Constant)
121
What is the speed of light in m/s?
3.0 x 10^8 m/s
122
How is fission achieved?
By bombarding the nucleus with neutrons
123
How is energy from fission typically used?
For electric power generation
124
What is fusion?
Fusion is the combination of two hydrogen atoms to make a bigger helium atom that creates a lot of energy
125
Where does fusion occur?
Only in the Sun and stars
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What is fission?
When an unstable neutron smashes into a different nucleus, breaking that nucleus into several neutrons which go off and break other nuclei
127
To avoid uncontrollable reactions, what do power plant workers do to the broken nuclei?
They contain the neutrons back into the nucleus
128
Why are circle contraptions more likely to have a fission reaction?
It is the most likely shape to have fission as it has the least surface area meaning fewer neutrons escape as everytime a neutron collides with the surface of a material, it has a chance of escaping
129
Why do larger contraptions have a higher chance of a fission reaction?
They have more space for more atoms which increases the chances as there are more atoms
130
Why is Uranium 235 (U235) commonly used in fission reactions?
It is the easiest isotope to find that can create a chain reaction
131
Why is Uranium 235 good for creating chain reactions?
Uranium is not stable (the nucleus is not stable)
132
Is Uranium 235 an Isotope?
Yes
133
What is isotope notation?
Mass number on top and the atomic number on the bottom
134
What is the fusion reaction chemical equation?
2/1 Hydrogen (H) + 2/1 Hydrogen (H) = 4/2 Helium (He) + energy
## Footnote
The elements are isotopes
135
What are the three hydrogen isotopes that can be used in nuclear fusion?
Protium (1H [0 neutrons]), Deuterium (2/1H), Tritium (3/1H)
136
What is Astronomy?
The study of stars
137
What are the properties of stars?
They vary in size, mass, temperature and brightness
138
What is a star?
A star is a giant ball of hot glowing gases
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What are most stars fully made of?
Hydrogen and Helium
140
How is the energy needed for nuclear fusion made in a star?
Through the gases constantly reacting
141
What happens when stars are born?
Their fuel (hydrogen) is changed to helium through nuclear fusion
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How are stars born/what is a nebulae?
From collapsing clouds of gas and dust, often called a nebulae
143
What are protostars and how are they formed?
Over time, the star absorbs gas as temperature and pressure increases, creating a rotating sphere of super hot gas known as a protostar
144
How are main sequence stars made?
When the protostar settles into a state of equilibrium, becoming what is known as a main sequence star
145
Protoplanetary disk
A rotating disk/ring of gas and dust that surrounds the protostar during the life cycle of a star (forms as/during the protostar is formed)
146
Globule
A tiny globe or ball in space
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Protoplanetary disk
A rotating disk of gas and dust
148
Russel Hertz diagram
Stars in the top left hand corner are brighter, hotter and larger than the sun which means it will run out of fuel faster. Stars in the bottom right corner dim, cool, and small which means it will live longer.
## Footnote
In this diagram the y-axis is different from normal graphs and so is the x-axis so make sure to read the diagram properly.
149
Doppler effect - Evidence for the big bang
The change in frequency or wavelength of a wave when the source is moving away from an observer just like when sound is loud when near us but quiet when moving away. When galaxies move away their light turns to the red part of the spectrum (called redshift) and nearly all galaxies have this suggesting that they are all moving away, yet must have come from one spot.
150
Nucleo synthesis - Evidence for the big bang theory
The theory of stars being created from simple elements (hydrogen and helium) and created into bigger things (like the big bang suggests)
151
Comic Microwave Background Radiation (CMB)- Evidence for the Big Bang
A 'baby' picture of the universe, showing the oldest light that we can see
152
Orbitals
Energy levels
153
In light, what does colour and energy have in common?
They are the same
154
How do electrons jump orbitals?
They need a specific energy level for each level jump, which requires a specific colour from the spectrum which is absorbed/emitted
155
Ground state
Lowest energy level in an orbital
156
What happens when light hits an electron?
The electron jumps an orbital level due to the energy being absorbed or emitted
157
How can the amount of energy absorbed by an electron in orbitals be calculated?
Since a specific energy is needed so is a specific colour, and on the colour spectrum, each colour has a frequency which can be used to calculate the energy absorbed by the electron.
THE EQUATION: E = HF (IF THE FREQUENCY IS UNKOWN THEN USE HF = E1 - E2 WHERE HF IS JUST ENERGY)
H = planks constant
F = frequency
E = energy
158
What happens when something emits light in orbitals?
It moves down orbital levels
159
Excited state
When an electron moves up the orbitals, it is excited
160
Continuous Spectrum
All the colours of the spectrum with no gaps in it
161
Absorption spectrum
Colour spectrum with black (dark) lines
162
Emission spectrum
Black spectrum with lines that are different colours
163
Is the amount of energy to move up the same as to move down in the orbital spectrum?
Yes
164
Atomic absorption Spectra
When atoms absorb energy, their electrons move to a higher energy level
165
Atomic Emission Spectra
The electrons lose energy by emitting light so they return to lower energy levels
166
What does each element differ in in terms of the absorption and emission spectra?
Absorption and emission lines
167
What happens on the absorption or emission spectra if two elements are combined?
The lines from their spectra are combined and represented in one spectra
168
Equation to find the photon's energy when it goes up or down the orbitals
Photon energy = (hf = E1 - E2)
hf = planks constant (just a value that is given) times frequency which can be found from colour (THIS GIVES THE PHOTON ENERGY AS THAT IS THE EQUATION FOR THAT)
E1 = initial energy level
E2 = final energy level
169
Principal quantum number (n)
Ground state (n=1) and as the orbital level increases, n=2, n=3, n=4 and so on
170
Frequency equation for photons
F = E/H
E = energy ( E1 - E2)
H = planks constant (just a value that is given)
171
In the absorption spectrum, what do the black lines show?
The colour being absorbed
172
In the emission spectrum, what do the coloured lines show?
The colours being emitted as an electron moves down orbitals
173
Fusion and where it occurs
When hydrogen atoms combine to create helium. This releases a lot of energy in the form of light and heat. This occurs in the Sun (and other stars like it).
174
Fission
Nuclear fission is when the nucleus of an atom splits into two smaller nuclei which go off to break down other nuclei. Fission creates energy and it is used in nuclear power plants.
175
Astronomy definition
Study of stars
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Star definition
A giant ball of hot glowing gases
177
What are most stars mainly/fully made up of?
Hydrogen and Helium
178
How is the energy needed for nuclear fusion made?
Through gases that constantly react
179
What happens when stars are born?
They go through nuclear fusion
180
3 Isotopes of Hydrogen
Protium (1/1H), Duterium (2/1H), Tritium (3/1H) MASS NO. ON TOP
181
What happens when hydrogen in a medium size star runs out?
The star stars to use helium and conducts helium fusion to create bigger and heavier metals but can only do this when a star has enough energy to do it and that energy is created through nuclear fusion
182
What causes the outer layers of a medium size star to expand and cool? THIS IS HOW A RED GIANT IS FORMED AS ONCE THIS HAPPENS THE STAR BECOMES BIGGER AND REDDER
Heat from fusion produces radiation pressure (where the heat [or any kind of radiation] doesn't just hit something, it PUSHES it - radiation pressure)
183
What does helium fuse into in a medium size star?
Heavier carbon
184
What is the state of a medium size star when it becomes a red giant?
It has a small dense core and a large outer atmosphere
185
How long until our sun becomes a red giant?
About 5 billion years
186
What happens to the outer layers of a medium size star when helium runs out?
They escape to become a planetary nebula
187
What is a white dwarf?
A dense core left after a star collapses
188
How does a white dwarf differ from a red giant?
A white dwarf is dimmer than a red giant
189
What happens when nuclear fusion ceases (stops) in a white dwarf?
It becomes a black dwarf
190
What is the equilibrium in a main sequence star?
Gravity and radiation pressure are balanced
191
What happens to the brightness of heavier main sequence stars?
They are hotter and brighter
192
How does mass affect nuclear fusion in stars?
Greater mass leads to faster fusion rates
193
What is the initial stage of a star's life cycle?
An interstellar cloud collapses
194
What forms when a protostar ignites nuclear fusion?
A main sequence star
195
What happens to a star after it burns through hydrogen?
Helium ignites explosively, forming heavier elements
196
What is formed when the outer layers of a star are ejected?
A colorful planetary nebula
197
What is a neutron star?
A star with a density from collapsed atoms
198
What happens to a supergiant star after it fuses material into iron?
It stops producing energy and collapses
199
What is a black hole?
A singularity with immense gravitational forces
200
How do black holes affect light?
They do not allow light to escape
201
What does the H-R diagram show?
The relationship between brightness and temperature
202
Where do stars start their lives on the H-R diagram?
Bottom right corner
203
What happens to stars when they run out of hydrogen?
They undergo a transformation off the main sequence
204
What is luminosity in relation to stars?
It measures total energy emitted by a star
205
How does the size of a star affect its luminosity?
Bigger stars are more luminous
206
What are the stages in the life cycle of a medium size star?
Nebula, Protostar, Main sequence, Red giant, Helium fusion, Planetary nebula, White dwarf, Black dwarf
207
What are the stages in the life cycle of a massive star (after the nebula, protostar, and main sequence)?
Helium Fusion, Blue Supergiant, Supernova, Neutron star or black hole
208
What are the differences between a neutron star and a black hole?
Neutron star: 1.4-3 times solar mass, dense; Black hole: >3 times solar mass, singularity
209
What is the significance of the H-R diagram in stellar evolution?
Shows relationship between brightness and temperature; Helps classify stars based on their life stages
210
What does it mean for a protostar to set into a state of equilibrium?
When the nuclear fusion in the protostar is pushing it outwards yet gravity is pulling everything inwards, causing a state where the star is not shrinking or growing
211
What does the top left of a H-R diagram show?
Stars that have a high temperature and high luminosity
212
What does the bottom right of the H-R diagram show?
Stars that are cooler and have less luminosity
213
How may a star have less temperature, yet more luminosity?
More area increases luminosity, so in certain situations it can have more luminosity even with a less temperature, however temperature increases luminosity A LOT MORE than area.
214
Proper life cycle of a star
Nebula, Protostar, Main sequence star; After that it depends on the star's MASS (medium-sized star, massive stars)
215
What is the frequency and wavelength size of a sound moving away from us?
The frequency is low and it has a long wavelength
216
What is red shift?
When matter is stretching (happens when sound moves away from us and the frequency is low/wavelength is also long)
217
On the colour spectrum, from blue to red, what is the frequency and wavelength across the spectrum?
On the left side the blue shows a high frequency and a short wavelength and the right side with red shows a low frequency and a long wavelength.
218
What is redshift in light?
Light shifted towards lower frequencies
219
What happens to wavelengths during redshift?
Wavelengths increase and frequencies decrease
220
What causes cosmological redshift (stretching of light waves)?
Expansion of space
221
What are the three types of redshift?
Expansion of the universe, galaxy movement, gravitational redshift
222
What is blueshift in light?
Light shifted towards higher frequencies
223
What happens to wavelengths during blueshift?
Wavelengths decrease and frequencies increase
224
Can blueshift be seen with the naked eye?
No, it requires wavelength study
225
What instruments are used to study blueshift and redshift?
Spectrometer or spectrograph
226
What do redshift and blueshift refer to?
Redshift: shift away from us, higher wavelength, lower frequency; Blueshift: shift towards us, lower wavelength, higher frequency
227
How do redshift and blueshift relate to light wavelengths?
They indicate direction of wavelength shifts
228
How is the Doppler effect used in astronomy?
To determine the movement of celestial objects
229
What is the significance of red and blue in redshift and blueshift?
Red: shift away from the observer; Blue: shift towards the observer
230
Redshift definition
A shift of light towards lower frequencies and longer wavelengths (the red end of the spectrum). Happens when an object is moving away from an observer.
231
Blueshift definition
A shift of light towards higher frequencies and lower wavelengths (the blue end of the spectrum). Happens when an object is moving towards the observer.
232
Plank Epoch
No space and no time
233
GUT Epoch
Universe expands (field-inflation) and we get gravity and then strong force
Universe is still hot.
234
Electroweak Epoch
No mass but there is electromagnetic force
Materials needed to make atoms are present
235
Quark Epoch
Mass starts and Higs field is created (a special field that gives things mass)
236
Hadron Epoch
Hadrons (particles) are present (protons and neutrons are present as they are hadrons)
All the matter in the universe are present.
237
Order of the Epochs (life cycle of the Big Bang)
Plank Epoch
GUT Epoch
Electroweak Epoch
Quark Epoch
Hardon Epoch
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