physics paper 1 Flashcards
1
Q
In 1897 what did J J Thomson discover could be removed from atoms?
A
electrons
2
Q
Due to J J Thomson discovering that electrons could be removed from the atom what model did he suggest?
A
A plum pudding model
3
Q
Whose model of the atoms is most like our model of the atom today?
A
Bhors model
4
Q
What did experiment did Rutherford? (decay)
A
They shot a beam of alpha particles at gold foil, they thought more would go through the expected but didn’t expect some to deflect back.
5
Q
what is the relative mass and relative charge of a proton?
A
relative mass=1 and relative charge=+1
6
Q
what is the relative mass and relative charge of a neutron?
A
relative mass=1 relative charge=0
7
Q
what is the relative mass and relative charge of an electron?
A
relative mass=0.0005 relative charge=-1
8
Q
When do we call an atom ionised?
A
When it loses an electron.
9
Q
What sort of radiation ionises atoms?
A
Nuclear radiation.
10
Q
What are isotopes?
A
The different form of the same element, they have a different amount of protons.
11
Q
What radioactive substances are spat out after ionising radiation?
A
alpha, beta, gamma or neutrons are spat out.
12
Q
What is an alpha particle made up of?
A
two neutrons and two protons
13
Q
What does alpha decay decrease?
A
the charge and the mass of the nucleus
14
Q
What does beta-minus decay increase?
A
The charge of the nucleus.
15
Q
What does a positron emission do?
A
it decreased the charge of the nucleus
16
Q
what does a neutron emission do?
A
It decreases the mass of the nucleus.
17
Q
What does a short half life mean?
A
It means that the activity will fall quicker as the nuclei are more unstable and rapidly decay
18
Q
Why is a short half life dangerous?
A
It is dangerous because it means more radiation is emitted over a shorter period of time.
19
Q
What does a long half life mean?
A
It means that the activity will fall more slowly as the nuclei will not decay for a long time.
20
Q
How can you measure half life?
A
Using a graph
21
Q
What is it called when you are exposed to radiation?
A
Irridation.
22
Q
How does radiation damage cells?
A
by ionisation
23
Q
Which two radiations can penetrate the body and get to vital organs?
A
beta and gamma
24
Q
In house hold fire alarms what radiation do they use?
A
Alpha radiation
25
If a radioactive source has a lower activity what does it mean?
It is safer to be around
26
How does a fire alarm work?
The smoke will absorb the radiation and this stops the current in the alarm causing it to set off.
27
why must all isotopes entering the body be beta or gamma?
So that they can leave the body
28
What is PET short for
Positron emission tomography
29
What can a PET scanner be used for?
To help diagnosis and help identify medical conditions, ie it can help identify cancer cells.
30
what does the positron do when in the body? (6 marker)
The positron will find and meet electrons in the organs and will annihilate them. it emits high energy gamma rays, in opposite directions . these are detected, detectors around the body identify each gamma ray and the tumour will lay along the same path, if three pairs are detected it can help locate the tumour more accurately.
31
Is radiation used internally or externally to treat tumours?
both
32
why are isotopes used in PET scanning need to be transported quickly?
Because they have a short half life so either need to be made on site or close by. They have short half life so the isotope doesn't stay in the person's body long.
33
Where are alpha emitters injected when used in treatment?
Near the tumour
34
How are beta emitters normally sued in treatment?
As implants.
35
What is nuclear fission?
The splitting up of a big atomic nuclei.
36
What particle is an unstable nucleus normally shot at?
uranium 235
37
What happens every time after an unstable nucleus hits uranium 235
The atoms splits up and spits out two or three more neutrons and these can hit another uranium 235 particle continuing the chain reaction
38
What is nuclear fusion?
two light nuclei collide at a high speed and join together to create a heavier nucleus?
39
what happens to some of the mass after nuclear fusion?
Some of the mass from the lighter nuclei is converted into energy then released as radiation.
40
True or false fusion only happens at high temperatures and pressures?
True
41
why does fusion only occur at really high temperatures?
because the positively charged nuclei have to get very close to fuse so need to overcome the strong electrostatic force.
42
What temperature does nuclear fusion tend to happen at?
10 000 000 degrees celsius yes 10 million degrees celsius
43
Why are people scared of nuclear power?
The products of nuclear fission have very long half lifes meaning they will be radioactive for thousands of years.
44
what threat does nuclear power have with the environemnt?
Due to it needing to be carefully disposed and its long half life it could potentially leak and spill into rivers, oceans and spread across land and it would affect all wildlife.
45
What are some major nuclear power catastrophes?
Chernobyl and Fukushima
46
True or false nuclear power is more safe than most people think?
True it is a pretty safe way of generating electricity.
47
what does nuclear fission not do that fossil fuels do?
Fossil fuels release lots of carbon dioxide contributing to global warming and the greenhouse effect.
48
what does nuclear fission not do that fossil fuels do?
Fossil fuels release lots of carbon dioxide contributing to global warming and the greenhouse effect.
49
True or false nuclear fission is extremely costly?
False it is relatively cheap, only takes a small amount to create loads of energy.
50
What counteracts the cheapness of nuclear fission?
It has an overall high cost due to the cost of the power plant and decommissioning of the power plants as dismantling a power plant safely could take a very long time.
51
What's dwarf planet and give an example?
A planet not big enough to be a planet, like Pluto.
52
What is a natural satellite in space?
Moons
53
What is the name for a human made satellite that is in space?
an artificial satellite.
54
What is an asteroid?
lumps of rocks and metals, often in asteroid belts and they orbit the sun.
55
What is a comet made of?
lumps of ice and dust.
56
What model suggested everything orbited the sun?
Geocentric model
57
What is the steady state theory?
Matter is always being created and that the universe always existed as it is now ad as the universe expands new matter is made.
58
what is the big bang theory?
All matter in universe was in a small place and was dense, it exploded creating everything we know and it still is exploding.
59
What suggest that the universe is still expanding?
Red-shift
60
What is the definition for red-shift?
an observed increase in wavelength of the light coming from the galaxies and patterns have shifted towards the red end of the spectrum.
61
What do measurements of red shift tell us?
distant galaxies are moving away from us quickly
62
What does CMB stand for?
Cosmic microwave background radiation
63
What does the big bang model tell us about CMB radiation?
It says that CMB is left over energy from the explosion.
64
What is the life cycle of a star?
A cloud of dust and gas forms a nebula. nebula - protostar - main sequence star - either a red giant - white dwarf or a red supergiant after the main sequence star. red supergiant - supernova - neutron star or a black hole.
65
What's a nebula made of?
dust and gas
66
How does a protostar form?
gravity pulls the dust and gas together, temperature rises as star gets denser when temp is high enough nuclear fusion occurs, lots of energy given out keeps core of star hot.
67
How does a neutron star form?
when the supernova explodes it throws outer layers and leaves a dense core called a neutron star.
68
how does a black hole form?
When the supernova explodes if star is massive enough it collapse creating black hole.
69
what forms when a small-medium sized star becomes unstable and ejects the outer layer of dust and gas?
A white dwarf forms.
70
What are telescopes used for?
To view the universe and help discover more about the world
71
What are advantages with land telescopes?
They are on land so easy to repair and do not have to send them into space saving money.
72
what are disadvantages with land telescopes?
atmosphere can blur images due to light pollution and ozone layer.
73
what are advantages with space telescopes?
Clearer images due to no light pollution,
74
what are disadvantages of space telescopes?
Harder to repair as they are in space, cost more money to build as have to be able to work in space and not get broken easily.
75
How does a main sequence star form?
star has entered a long stable period, outward pressure caused by thermal expansion tries to expand the star.. it balances and gravity pulls everything inwards. the main sequence star lasts for several billion years, a heavier star has a shorter main sequence.
76
Where is the best place to put a telescope on earth?
on a mountain in a dark place away from cities.
77
What are x-ray telescopes used for?
high temperature events like an exploding star.
78
What telescopes was responsible for the discovery of cmb?
radio telescope
79
True or false a bigger telescope means a bigger resolution
True
80
what is the EM spectrum
radio waves, microwaves, infrared radiation, visible light, ultraviolet light, x-rays, gamma rays,
81
What are the two types of wavelengths?
Transverse and longitudinal
82
Is the transverse a P or S wave?
It is a S wave
83
is a longitudinal wave a S or P wave?
It's a P wave
84
What is the amplitude of a wave?
The distance from the rest position to either the peak or the trough.
85
What is a wavelength?
A full cycle of the wave from crest to crest or trough to trough.
86
What is wave speed measured in?
m/s
87
what is wavelength measured in?
m
88
what is frequency measured in?
Hz
89
What is time measured in waves?
seconds
89
What happens to waves at boundaries?
They are either absorbed, transmitted or reflected
90
What does an objects: size, shape and structure determine about frequency?
What it determines is what frequency the object can be transmitted.
91
True or false frequency changes when going through a new medium?
False
92
What does change when a wave goes through a new medium?
It gets longer when the wave speeds up and shorter when it slows down.
93
Can sound travel in a vacuum? Why or why not?
It can not travel in a vacuum (space) because there are no particles for the sound to vibrate.
94
What are echoes?
Reflected sound waves
95
What is ultrasound?
Ultrasound is a frequency higher than 20,000 Hz
96
What happens to ultrasound waves at boundaries?
They get partially reflected.
97
How is ultrasound used in detecting foetuses?
The waves pass through the body, but when they reach a boundary between 2 mediums some of the wave will be reflected and the rest is detected on a screen.
98
How is ultrasound used in industrial imaging?
It is used to find flaws in objects like pipes or materials made of wood or metal.
99
How does the ultrasound work in industrial imaging?
If there is a crack in the objects the waves from the sound will be deflected sooner.
100
what sound has a frequency lower than 20Hz?
Infrasound
101
What is an example of an animal that communicates in ultra sound?
Whales and elephants
102
What sort of waves do earthquakes and explosions create?
seismic waves
103
What is faster a P or S wave?
P waves are faster.
104
What can P waves travel through?
Solids and liquids.
105
What can S waves travel through?
only solids
106
What is the angle of incidence equal to?
The angle of reflection
107
How do you work out the angle of reflection?
measure the angle between the reflected wave and the normal
108
what does total internal reflection depend on?
The critical angle.
109
When can total internal reflection occur?
When a wave travels through a dense material towards a less dense material
110
What happens when the angle of incidence is less than the critical angle?
light is refracted
111
What happens when the angle of incidence is equal to the critical angle?
ray goes along the surface
112
What happens when the angle of incidence is larger than the critical angle?
Total internal reflection occurs
113
What is specular reflection?
when waves are reflected in a single direction by a smooth surface.
114
what is diffuse reflection?
when waves are reflected by a rough surface in all directions.
115
What is white light made off?
all the different colours of light
116
How many colours are reflected by the colour white?
All colours
117
How many colours are absorbed by black objects?
All colours
118
If a colour filter is not a primary colours what colours are let trough?
The colour of the filter and the colours that make up the filter
119
When is a real image formed?
When light rays come together to form an image
120
When is a virtual image formed?
When light rays from the object appear to be coming from a completely different place.
121
How can a power of a lens increase?
With its curvature.
122
What does every object absorb and emit?
EM Radiation
123
What does radiation do to earth?
It affects its temperature
124
What is a better emitter black or white surfaces?
Black surfaces are better emitters
125
what is the frequency of a wave?
The number of waves produced per second.
126
What is the period of the wave?
The time it takes for two successive crests (one wavelength) to pass a specified point.
127
difference between longitudinal and transverse waves?
transverse are perpendicular to the direction of wave travel and longitudinal are parallel to the direction of wave travel
128
What affects an object's ability to transmit given frequencies of a sound?
what the object is made from and its properties
129
True or false opaque objects transmit light?
False opaque objects do not transmit light
130
What happens to white light when it hits a white object?
All aspects of the white light will be equally reflected
131
How do colour filters work?
When white light passes through a coloured filter, all colours are absorbed except for the colour of the filter.
132
What does real image mean?
an image that can be projected onto a screen.
133
What does virtual image mean?
A virtual image cannot be projected onto a screen. It appears to come from behind the lens and can only be seen by looking through the lens.
134
How does a lenses curve affect its power?
The larger the curve the more power the object has
135
True or false Diverging lenses will always produce a real image
False it always produces a virtual image
136
True or false all electromagnetic waves are are transverse?
True all EM waves are transverse
137
Give a potential danger of uv radiation?
UV radiation is dangerous because it is ionising and can damage skin cells on the surface can lead to skin cancer
138
potential danger of x-rays?
use gamma rays which are ionising can cause mutations and damage to cells
139
potential dangers of gamma rays?
can pass through skin and deeper tissues and mutate and damage cells
140
describe the average power of absorption for objects at room temperature?
radiates and absorbs an average power if a room is at a constant temperature
141
describe the average power of radiation for objects at room temperature?
equal when at constant temperature
142
How does absorption affect the earth's temperature?
it increases the temperature of the planet
143
How does reflection affect the earth's temperature?
it cools the planet slightly
144
How does emission of radio waves affect the earth's temperature?
Most of the emitted longwave radiation warms the lower atmosphere, which in turn warms our planet's surface.
145
Give uses of gamma rays?
medicines, sterilization, disinfection
146
what type of radiation is used in thermal imaging cameras?
infrared
147
what kind of current is used to generate radio wave in an antenna?
oscilating electric current
148
What is the difference between scalar and vector quantities?
vector has direction and magnitude wereas scalar is only magnitude
149
what does acceleration mean in terms of velocity?
change in speed of an object over a certain time
150
what does acceleration mean in terms of time?
the change in velocity of the object over time
151
what does a gradient represent on a distance/time graph?
speed
152
what does a gradient represent on a velocity time graph?
acceleration
153
How do you find the distance travelled by an object from its velocity/time graph?
the area of the section underneath
154
What is Newton's first law?
An object at rest remains at rest, or if in motion, remains in motion at a constant velocity unless acted on by a net external force.
155
What is Newton's second law?
F=MA
156
What is Newton's third law?
two objects inertacting will exert equal and opposite forces
157
Why do cars have safety features to reduce de-acceleration of passengers?
so that when the car slows down the person doesn't continue at the same momentum and get injured as they would ne flung out the car
158
What is the formula for calculating the weight of an object?
W = mg
159
why must there be a force acting to produce a circular motion?
velocity is a vector and the direction of the object is constantly changing
160
What is the name of the force that creates a circular motion?
centripetal force
161
What is inertia?
a resistance to a change in motion
162
what is meant by a person's reaction time?
How quickly a person can react to a scenario
163
state things that can affect thinking distance?
tiredness, alcohol, drugs, distractioms, speed
164
state things that can affect braking distance?
speed, mass of the car, brake condition, friction of tire.
165
what is meant by dissipation of energy?
how energy is wasted
166
Give energy transfer for when a hair dryer is switched on?
electrical energy to thermal energy
167
How does the thermal conductivity of a wall affect its rate of energy?
the higher the thermal conductivity the higher the rate of reaction
168
what are bio fuels made from?
plant materials that are not safe to be consumed by humans
169
what is the difference between nonrenewable and renewable energy resources?
renewable energy is a lot safer and better for the environment and can be mad eover again and re used where as nonrenweable energy is more dangerous for the environment and can not be re used once used to create energy
170
what is a system?
an object or group of objects
171
give 3 ways energy of a system can be changed?
chemical recation, heating, electrical work,
172
how do you convert joules to nanometres?
you can not joules are energy nanometres are distance
173
what is interaction pair?
a set of two forces that are in opposite directions, have equal magnitudes and act on different objects.
174
what is a free body force diagram?
the forces acting on an object
175
what is the resultant force of an object in equilibrium?
0 Newtons
176
what is meant by the resultant force acting on an object?
overall force that acts on an object
177
true or false a mechanical process becomes wasteful when it causes an increase in temperature?
True
178
define power
amount of energy transferred per unti time
179
what unit is power measured in?
Watts
180
True or false friction is a non contact force?
True
181
True or false a moment is a turning effect force?
True
182
what is the principle of moments?
when a body is balanced, the total clockwise moment about a point equals the total anticlockwise moment about the same point
183
how do levers make it easier to do work?
by changing the force applied to the machine or the distance over which the force is applied.
184
true or false for a given force a larger gear will turn slower than a small gear?
True
185
if gear one is spinning clockwise what direction will gear 2 turn?
anticlockwise
