Paper 1 Flashcards
(230 cards)
1
Q
SP1a - What are the five main scalar quantities?
A
Speed Mass Time Distance Temperature
2
Q
SP1a - What are the six main vector quantities?
A
* Velocity * Displacement * Acceleration * Force * Weight * Momentum
3
Q
SP1a - What is a scalar quantity?
A
A quantity with a magnitude (size) but no direction
4
Q
SP1a - What is a vector quantity?
A
A quantity with a magnitude (size) and direction.
5
Q
SP1b - How do you work out average speed?
A
Speed (m/s) = Distance(m) / Time(s)
6
Q
SP1b - On a distance/time graph, what does a curve represent?
A
The object is accelerating/deccelerating
7
Q
SP1b - On a distance/time graph, what does a horizontal line tell us?
A
The object is stationary
8
Q
SP1b - On a distance/time graph, what does the gradient represent?
A
The velocity
9
Q
SP1b - What are the two things you can use to measure speed in an experiment?
A
* Stopwatch * Light gates
10
Q
SP1b - What is the average speed of walking and cycling?
A
* Walking: 1.4m/s * Cycling: 6m/s
11
Q
SP1b - What is the speed of sound?
A
340 m/s
12
Q
SP1c - How do you calculate acceleration?
A
Acceleration (m/s²)=Change in velocity (m/s) ÷ Time (s)
13
Q
SP1c - What is the value of acceleration due to gravity?
A
9.8m/s² (rounded to 10m/s²)
14
Q
SP1d - What does a curve mean on a velocity time graph?
A
Changing acceleration
15
Q
SP1d - What does a horizontal line mean on a velocity time graph?
A
The object is moving at a constant velocity
16
Q
SP1d - What does a straight slope mean on a velocity time graph?
A
Constant Acceleration
17
Q
SP1d - What does the area under a velocity time graph represent?
A
The distance covered
18
Q
SP2a - If a rocket experiences 800kN of thrust upwards and its weight is 300kN, what is the resultant force?
A
800 is up 300 is down.800 - 300 = 500500kN upwards
19
Q
SP2b - How can the amount of centripetal force needed for an object to remain in circular motion be altered?
A
The amount of force needed increases if you: * Increase the mass of the object * Increase the speed of the object * Decrease the radius of the circle
20
Q
SP2b - What is centripetal force?
A
* A force that causes objects to follow a circular path. The force acts towards the centre of the circle
21
Q
SP2b - What is Newton’s first law?
A
* A moving object will remain at a constant velocity until an external force acts on it. * A stationary object will remain stationary until an external force acts on it.
22
Q
SP2b - What three things can provide centriputal force?
A
* Tension * Friction * Gravity
23
Q
SP2c - Describe the forces acting on a skydiver as they jump out of a plane
A
As soon as they jump out, the only force acting on them is their weight and so they accelerate downwards Air resistance increases with speed and so as they accelerate, air resistance increases until eventually it is equal to their weight At this point the resultant force acting on the skydiver is 0 and so they stop changing velocity as they have reached terminal velocity Once the parachute is launched, the air resistance greatly increases causing a decceleration As the velocity decreases so does the air resistance until it is again equal to the weight It now reaches a new lower terminal velocity
24
Q
SP2c - What formula links weight and mass?
A
w = m x g(Weight = mass x gravitational field strength)
25
SP2c - What is the difference between weight and mass?
Mass is the quantity of matter in an object and weight is the pull force the object experience depending on the gravitational field strength.Weight - NMass - Kg
26
SP2d - What equation uses Newton's second law?
F = m x a(Force = mass x acceleration)
27
SP2d - What is inertial mass?
\* The mass of an object found from the ratio of force divided by accelaration
28
SP2d - What is Newton's second law of motion?
The acceleration of an object depends on: \* Its mass \* The Force acting on it
29
SP2d CP - How can you investigate the acceleration of a trolley using light gates?
\* Attach masses to the end of the trolley hanging off the end of the table over the ramp and the pulley . \* Set up two light gates measured distance apart. \* Connect the light gates to a data logger. \* Release that masses. using your data log information, divide the length of the card by the time the light gate was active for each of the light gates. \* Divide the difference between these two velocities by the time between each of them to get the acceleration. \* To investigate how mass affects this, repeat with different masses.
30
SP2d CP - When investigating how the mass of trolley affects acceleration, what's one thing we need to keep the same to make it fair?
The angle of the wooden block
31
SP2e - What is Newtons third law?
\* Every action has an equal and opposite reaction
32
SP2e - What is the difference between balanced forces and action-reaction forces?
Balanced forces all act on the same object, action-reaction forces act on different objects.
33
SP2e - When a person is standing, describe the action-reaction forces.
The downward force of weight from the person on the ground and the upward reaction force of the ground on the person.
34
SP2f - What equation connects force and momentum, and how can this be derived?
F = Δp / t(Force = change in momentum ÷ time)As F = m x aand a = Δv / twe can see thatF = (m x Δv) ÷ tSince m x v = pthen m x Δv = ΔpSo, F = Δp ÷ t
35
SP2f - What is the formula for momentum?
p = m x v(momentum [kg m/s] = mass x velocity)
36
SP2f - What is the law of the conservation of momentum, and how is this affected by the fact that momentum is a vector quantity?
\* Total momentum before = total momentum after \* Since momentum is vector, an object moving in the opposite direction has a negative momentum and this must be taken into account when calculating momentum.
37
SP2g - What can increase the braking distance of a car?
Increasing its momentum: \* If it is moving faster \* Higher mass Reducing friction: \* Brakes are worn \* Rain/ice/snow on the roads \* Loose gravel
38
SP2g - What is stopping distance?
\* The total distance it takes for a car to stop once the driver reacts to an external stimuli. \* This consists of: Thinking distance & braking distance
39
SP2g - What is the average reaction time to visual stimuli and what can affect this?
\* 0.25 seconds. \* This can be longer if the driver has taken drugs/ alcohol or hasn't had enough sleep
40
SP2h - How can you combine the formulae for work done and KE to have a formula for braking distance?
E = F x dKE = 1/2 x m x v²(1/2 x m x v²) ÷ F = dd = (m x v2) ÷ 2FMass x velocity² divded by 2 force = braking distance
41
SP2i - Explain how the safety features of a car link to the equation linking force and momentum.
\* F = Δp / t \* All the safety features of a car absorbe kinetic energy, increasing the time taken for the momentum to reduce. \* As the time is increased, the force is reduced.
42
SP2i - What are the four main safety features of a car?
\* Air bags \* Crumple zones and side impact bars (Easily give way causing themsleves to crush) \* Seat belts
43
SP3a - By what processes can energy be transferred?
\* Heating \* Forces \* Electricity \* Light \* Sound
44
SP3a - What are the 9 energy stores?
\* Kinetic \* Thermal \* Gravitational Potential \* Elastic Potential \* Sound \* Light \* Chemical \* Nuclear \* Electrical
45
SP3a - What diagram might you use to display the transfer of energy?
A sankey diagram, The width of the bars represent the amount of energy.
46
SP3a - What is the law of the conservation of energy?
\* Energy cannot be created or destroyed, only transferred between stores. \* In a closed system, the total start energy = the total end energy
47
SP3a - What is unit for measuring energy?
Joules (J)
48
SP3b - How do you calculate efficiency?
total useful energy output / Total energy inputEfficiency is on a scale of 0 to 1. To calculate it s a percentage, x100
49
SP3b - How do you distiguish useful and wasted energy on a sankey diagram?
The useful energy has an arrow going staright while the wasted energy arrow turns off.
50
SP3b - What is it called when energy transfers to its surroundings by heating?
Dissipation
51
SP3b - What is the most common form of wasted energy?
Thermal
52
SP3b - What might you do to moving parts to reduce energy loss and why?
\* Use a lubricant. \* Moving parts cause friction which causes energy to dissipate losing energy. \* Lubrication reduces friction and thus energy loss by friction.
53
SP3c - What are the 3 different ways in which energy is transferred by heating?
\* Convection - This is when part of the fluid that is warmer than the rest rises up and creates a convection current \* Conduction - This is when vibrations are passed on between particles in a solid \* Radiation - The only way in which energy can be transferred through a vaccuum. Infrared radiation can also pass through gases and some solid materials.
54
SP3c - How is a flask able to maintain the temperature of its contents?
\* Silver coating on the outside and inside reflects radiation which would transfer thermal energy \* Glass walls with vacuums between create a cavity stopping heat from entering or escaping \* Plastic stopper stops heat from escaping
55
SP3c - Why do cavities in walls help insulate a house?
\* It creates an air gap - air has a very low thermal conductivity. When air is trapped, it cannot form convection currents and so does not transfer much energy
56
SP3c - What factors affect the rate of which energy is transferred through a material by heating?
\* The material's: - Thicknessrate of energy transfer is reduced by increasing thickness- Thermal Conductivityrate of energy transfer is reduced by decreasing thermal conductivity- Temperature Difference across itrate of energy transfer is reduced by decreasing temperature difference
57
SP3d - As an object falls describe the change in energy stores in terms of GPE and KE.
\* As an object looses height, it looses GPE this 'lost' energy transfers, mostly, into kinetic energy as it is moving. \* Some other energy may transfer into sound energy
58
SP3d - What is the formula for change in gravitational potential energy.
ΔGPE = m x Δh x g(change in GPE is mass x change in height x gravitational field strength)
59
SP3d - What is the formula for Kinetic energy?
KE = ½ x m x v²(Kinetic energy = mass x velocity² divided by 2)
60
SP3d - What is the gravitational field strength on earth?
9.81 (Can be rounded to 10) m/s² or N/Kg
61
SP3e - Apart from the lack of sustainability, why is burning fossil fuels not beneficial?
It releases Carbon dioxide and other gases that are harmful for the environment as they contribute to climate change.
62
SP3e - What are the four main types of non-renewable energy sources?
Fossil fuels: \* Natural gas \* Coal \* Oil \* Nuclear
63
SP3f - What are the pros and cons of biofuel?
Pros: \* Will never run out \* Carbon neutral (Burning fuels releases carbon put planting plants took in carbon so its neutral) \* Useful as they can power vehicles Cons: \* Can take up space that could be used for food, this can increase the price of food.
64
SP3f - What are the pros and cons of hydroelectric energy?
Pros: \* Very reliable \* Will never run out \* Won't release carbon dioxide once installed Cons: \* Habitats destroyed \* Only useful when water sources are nearby
65
SP3f - What are the pros and cons of Tidal energy?
Pros: \* Extremely reliable \* Will never run out \* Won't release carbon dioxide once installed Cons: \* Some argue that it harms wildlife
66
SP3f - What are the pros and cons of using solar panels and solar energy?
Pros: \* Will never run out \* Won't release carbon dioxide once installed Cons: \* Energy output depends on sun and so may not always be available
67
SP3f - What are the pros and cons of using wind turbines?
Pros: \* Will never run out \* Won't release carbon dioxide once installed Cons: \* Many have to be installed and they have low output \* Takes up large spaces and soem say this spoils the view \* Not reliable
68
SP3f- Describe how Bio-Fuels work
Bio-Fuels are used in the same way as fossil fuels - they are made from animal wastes or from plants
69
SP3f- Describe how electricity is generated using Tidal Power
Tidal power can generate electricity when turbines in a dam across a river estuary turn as the tides flow in and out
70
SP3f- Describe Hydroelectricity
This is generated by falling water in places where water can be trapped in high reservoirs
71
SP3f- Describe the use of Solar Energy
Solar cells in solar panels convert solar energy directly into electrical energy, in ''solar farms'' or on house roof-tops.
72
SP4a - Descirbe the following features of a transverse wave: \* Frequency \* Period \* Wavelength \* Amplitude
\* The amount of waves passing in a second (measured in Hertz Hz. Determines pitch or colour) \* The time it takes one wave to pass a point \* The length in m from one point to the next identical point of a wave \* The distance in m from a waves rest position to its trough or peak
73
SP4a - Describe a longitudinal wave, giving examples.
\* Particles vibrate parallel to direction of travel \* Areas of compression and rarefraction \* Sound waves \* Seismic P waves
74
SP4a - Describe a transverse wave, giving examples.
\* Particles vibrate perpendicular to their direction of travel. \* They transfer energy They all travel at the same speed in a vacuum (3x108) \* All EM waves are examples of this \* Water waves are transverse
75
SP4b - Using two buoys, how can you measure the speed of waves?
\* Measure the distance the buoys are apart. \* Record the amount of time it takes for a single wave to get from one to the other. \* Do distance/time to get the wave speed.
76
SP4b - What are the two formulas for wave speed?
v = d/t(Velocity = distance ÷ time)v = f x λ(Velocity = frequncy x wavelength)
77
SP4b CP - How can you use a metal rod to investigate the speed of waves in solids?
\* Suspend a metal rod using clamp stands \* Hold a smartphone with a frequency app at one end \* Hit the other end of the rod with a hammer and record the peak frequency \* Meausure the length of the rod \* Frequency x wavelength
78
SP4b CP - How can you use a wave tank to investigate the speed of waves?
\* Set up a wave tank filled with water and a straight dipper with a ruler along the side \* Vary the voltage provided to the straight dipper till there are at least 2 waves visible at any point \* Count how many waves form in 10 seconds and divide by 10 to get your frequency \* Using the ruler estimate the wavelength of a wave \* Frequency x wavelength \* Alternatively, record how long it takes the wave formed to travel a certain distance and to distance/time
79
SP4c - How does refraction occur?
\* When a ray of light reaches an interface (boundary) between substances, it changes speed (because light's speed is dependant on the density of the substance it travels in). \* If it slows down it bends towards the normal and if it speeds up it bends away
80
SP4c - Using water waves as a model, explain why refraction occurs.
\* Waves of water travel faster is deeper water than shallow water \* They also are longitudinal so can be represented with lots of parallel lines rather than one line \* When the wave of water reaches a boundary between shallow and deep, the part of each line that is furthest ahead, will reach the boundary first and slow down first. \* This gradual change in which parts slow down means that the wave bends towards the normal
81
SP4d - What are the definitions of the following: \* Reflect \* Refract \* Transmit \* Absorb
\* Reflect: The waves bounce off \* Refract: The wave passes into the new material but changes direction \* Transmit: The wave passes through without being absorbed or reflected \* Absorbed: The wave disappears as the energy it was carrying is transferred into the material
82
SP4d - Why is a prism able to split white light into a spectrum?
Each frequency of light changes speed at a slightly different rate meaning that at the right angles they can be split up
83
SP4e - Describe the process of a sound being heard by and ear. [6 marks]
\* Sound waves enter the ar canal which focuses it \* The eardum is a thin membrance which vibrates due to the soundwaves' vibrations \* Vibrations are passed on to tiny bones which amplify the vibrations \* Vibrations are passed on to the liquid inside the cochlea \* Tiny hairs inside the cochlea detect these vibrations and convert them to electrical impulses \* Impulses travel along the auditory nerve to reach the brain
84
SP4e - Explain why as people get older, their range of hearing may decrease.
\* As people get older, the hairs of the base and apex of their cochlea can get damaged. \* This means that they are no longer able to convert vibrations into impulses \* Thus they can't hear these sounds
85
SP4e - How does the cochlea work?
\* The cochlea has a membrane covered with hair cells \* Each hair cell is connected to a neurone so that when it detects a vibration of its frequency it creates and electrical signal \* The cochlea is a spiral with the outmost, thickest part (the base) detecting hgih frequencies (up to 20000Hz) and the low, thinnest end (the apex) detecting lower frequencies (down to 20Hz)
86
SP4f - How can boats use ultrasound in sonar equipment?
\* To find the depth of the water beneath them. \* They fire off an ultrasound wave at 1500m/s. \* They time how long it takes to return. \* They use d = s x t to find out the distance hte wave travelled and divide it by 2 to find the depth of the water
87
SP4f - How is ultrasound used in scans?
\* A probe emits ultrasound waves \* Gel is used to stop it from reflecting \* Some waves are reflected when they meet bones, fat, tissue etc. \* The probe also detects these refelected waves \* It sends these as impulses to the computer \* The ultrasound imaging machine detcts the frequency of the impulses turning it into an image
88
SP4f - What is the human range of hearing?
20Hz - 20,000 Hz
89
SP4f - What is ultrasound?
Sound above 20,000 Hz
90
SP4f - Why is an ultrasound scan more beneficial for scanning a foetus?
\* Other scans such as PET and CT would release radiation \* This could harm the foetus causing mutations
91
SP4g - How can seismic waves be used to detect earthquakes?
Seismic waves can be detected by seismometers and give information about where earthquakes are originating
92
SP4g - What are seismic waves?
Vibrations produces by earthquakes
93
SP4g - What are the two types of seismic waves and what is the difference?
\* P waves: Longitudinal \* S waves: Transverse
94
SP4g - What is a shadow zone?
The area where a wave cannot reach when fired from a point
95
SP4g - What is infrasound?
Sound below 20Hz
96
SP4g - What is the key thing to remember about seismic waves as they pass through the earth?
They get refracted
97
SP4g - Why are P waves more useful than S waves?
\* P waves are longitudinal while S waves are transverse \* S waves can only be transmitted by solids but P waves can go through all through states \* The earth has a liquid outer core \* S waves fired from a point can't go through the liquid core but P waves can \* This means that S waves have a larger shadow zone \* Using the idea that S waves can't go through liquids and P waves can, scientists were able to find out about the structure of the earth
98
SP4g - Why may there still be weak P waves even in the shadow zones?
They can be reflected by the solid inner core
99
SP4g - Why does the P wave shadow zone exist?
P Waves travel at a slower speed in liquid, so will refract (change direction), which creates the shadow zone.
100
SP5a - Describe total internal reflection.
\* When light passes from water or glass into air, the ray could be totally internally reflected. \* When the angle of incidence is greater than the critical angle, then the light is completed reflected inside the block.
101
SP5a - What do i and r represent in ray diagrams?
\* i: Angle of incidence (between incident ray and the normal) \* r: Angle of reflection/refraction (between reflected/refracted ray and the normal)
102
SP5a - What is the normal?
The line drawn perpendicular to the object light is reflecting off (or refracting through)
103
SP5a - What is the relation between the angles of incidence and reflection/refraction?
i = r (Angle of incidence = angle of reflection/refraction)This is the law of reflection
104
SP5a - What two processes can be shown using a ray diagram?
\* Reflection \* Refraction
105
SP5a CP - Describe a method to explore refraction with varying angles of incidence,
\* Place a ray box with a slit in front of it on a piece of paper \* Place a glass box the way of the ray of light thta is being produced \* Draw around the glass block \* Mark the point of entry and exit for the light aswell as two further points (such as origin and edge of paper) on the piece of paper \* Use your markings to draw lines representing the travel of the ray of light \* Repeat with ray box at different angles and compare your results
106
SP5b - Describe why a green object appears green in sunlight.
\* Sunlight is made up of white light as it contains all the colours of the visible spectrum \* An object that appears green will reflect the green part of the spectrum but abosrb all the other colours
107
SP5b - What are the two types of reflection?
\* Specular: When light is reflected evenly on a smooth surface \* Diffuse: When light is reflected in all directions on a rough surface
108
SP5b - Why do some objects appear black / white?
\* White objects reflect all colours \* Black objects absorb all colours
109
SP5c - When an object is placed more than 2F from a converging lens, what kind of image is created?
\* Diminished \* Inverted \* Real Image
110
SP5c - What does F mean on a ray diagram?
F is the focal length, i.e the length between the lens and its focal point
111
SP5c - What happens when an object is placed between 2F and F from a converging lens?
The image is: \* Magnified \* Real \* Inverted
112
SP5c - What happens when an object is placed less than F from a converging lens?
\* Magnified \* Virtual \* Right way up
113
SP5c - What type of image do diverging lens always form?
Images that are: \* virtual \* same way up \* much closer to the lens \* much smaller
114
SP5c - What is a lens, and what is its power?
A lens is a small piece of transparent material made to refract light in a certain wayThe power of a lens is how much it refracts light and is dependant on the shape and thickness of the lens
115
SP5c - What is the difference between real and virtual images?
\* A real image can be projected onto a screen whereas virtual image cannot be projected onto a screen. \* Real images are formed by light rays that come together. \* Virtual images seem to be on the same side of the lens as the object
116
SP5c - What is the focal point of a lens?
The point where all the rays of light would converge onto and meet.
117
SP5c - When an object is placed at 2F from a converging lens, what happens?
\* Real image \* Inverted \* 2F from other side of lens \* Same size \* (Photocopier)
118
SP5c - What is the difference between a converging (convex) and diverging (concave) lens?
Converging: Fatter in the middle and thinner at the top and bottom. Rays of light converge onto a focal point Diverging: Fatter at the top and bottom and thinner in the middle. Rays diverge away from each other once they pass through
119
SP5d - How were infrared waves discovered?
\* A prism was used to refract white light into the seven componets. \* A thermometer was placed just outside of the red part of this spectrum. \* Another was placed in the spectrum. \* The thermometer next to red was warmer suggesting there was something warming it up
120
SP5d - What are the similarities between all EM waves?
\* They are all transverse waves \* They all travel at (3x10^8m/s) ina vacuum \* They transfer energy
121
SP5e - List all of the EM waves in order of increasing wavelength/decreasing frequency.
\* Gamma rays \* X-rays \* Ultraviolet \* Visible light \* Infrared \* Microwaves \* Radio waves
122
SP5e - List all the colours in the visible light spectrum.
ROYGBIV Red Orange Yellow Green Blue Indigo Violet
123
SP5e - Why do different telescopes need to be used to study different EM waves?
EM waves of different length get absorbed by different amounts by the atmosphere
124
SP5f - How are radio waves produced?
\* Oscillations in electrical circuits. \* Metal rods can be used as aerials because they can absorb and transmit these oscillations
125
SP5f - What can infrared be used for?
\* Heating food \* Short range communication such as TV remotes \* Security systems
126
SP5f - What can microwaves be used for?
\* Communications and satellite transmissions \* Heating up food and giving it energy
127
SP5f - What can radio waves be used for?
\* Transmitting radio broadcasts \* Radio communications via satellites
128
SP5f - Whay can radio waves be used for longer ranges than microwaves?
\* The way radio waves and microwaves travel is dependant on the angles they reach the ionosphere. \* At all angles, microwaves pass straight through and so there is maximum range they can be fired in a straight line. \* At some angles, radio waves are reflected by the ionosphere, because they have larger wavelengths. \* This means they don't have to be fired directly to a point
129
SP5g - Describe the greenhouse effect in terms of radiation.
\* Energy from the sun is absorbed by the earth. \* The earth radiates this into the atmosphere \* Greenhouse gases in the atmosphere absorb this energy keeping it in the atmosphere \* This means that the earth doesn't radiate into the atmosphere the same amount of energy it absorbed \* Thus the temperature of the earth rises
130
SP5g - For the earth's temperature to stay constant what must happen?
The amount of radiation it absorbs from the sun must be equal to the amount of radiation that the earth radiates into space
131
SP5g - What is the difference between a hot and cold object in terms of radiation?
\* All objects emit the same amount of radiation that they absorb. \* Hotter objects will emit more radiation than cold objects in the same time
132
SP5g CP - Describe an experiment to explore how different surfaces absorb and emit infrared radiation using the following surfaces: \* Shiny black \* Shiny silver \* Dull black \* Dull grey
\* Pour water at 80° into four boiling tubes \* Cover each with one of the surfaces \* Put a thermometer in each \* Time it and record the temperautre at regular intervals \* The one that has the largest drop in temperature emits the most energy and thus must also absorb the most energy \* You would expect the results to be from largest to smallest change: \* Dull grey \* Dull black \* Shiny black \* Shiny silver
133
SP5h - What are the uses of gamma radiation?
\* Radiotherapy \* Sterilisation of medical equipment and food \* PET scanner
134
SP5h - What are the uses of Ultraviolet rays?
\* Disinfect waters by killing microorganisms \* Invisible ink due to fluoresence \* Security on bank notes
135
SP5h - What are the uses of x-rays?
Imaging of the inside of the body
136
SP5i - What are the dangers of infrared radiation?
\* Infrared radiation is absorbed by our body. \* We feel it as heat and an excess of it can destroy cells burning skin
137
SP5i - What are the dangers of ultraviolet light?
It can cause sunburn and damage to DNA which can lead to skin cancer
138
SP5i - What are the dangers of x-rays and gamma rays?
They can lead to mutations causing cancer.
139
SP5i - Why are UV x-rays and gamma rays dangerous?
\* They are ionising radiation. \* They large amounts of energy due to high frequencies and short wavelengths which can pass through our skin.
140
SP6a - What did the plum pudding model look like?
Made of positively charged mass with negatively charged electrons scattered throughout.
141
SP6a - What is the radius of a nucleus and the radius of an atom?
N: 1x10-15 A: 1x10-10 (Atom is 100,000 times bigger)
142
SP6a - What was the experiment that Erenest Rutherford conducted and what did he do?
\* The gold foil experiment. \* He fired alpha particles through various substances e.g. thin gold foil. \* Firing alpha particles from a source and having a detector behind whatever substance he used so that he could find out if the particles pass through.
143
SP6a - What were the results drawn of the gold foil experiment and what conclusions were drawn from this?
\* Most particles passed straight through \* Some were deflected slightly \* Others were bounced back \* This means that most of an atom is empty space. \* Aditionally, atoms have a concentrated area of positive charge. \* This is why some were reflected back.
144
SP6b - What are the charges, locations and relative masses of protons neutrons and electrons?
P: \* Inside nucleus \* +1 charge \* mass of 1 N: \* Inside nucleus, \* no charge \* mass of 1 E: \* Orbiting nucleus \* -1 charge \* mass of 1/1835 (negligible)
145
SP6b - What does the atomic number of an atom represent?
\* The number of protons in the nucleus. \* Different elements have different proton numbers
146
SP6b - What does the mass number of an atom represent?
\* The total number of protons and neutrons in the nucleus of the atom
147
SP6b - What is an isotope?
\* Atoms of the same element that have the same number of protons but different number of neutrons
148
SP6c - How will the emission spectrum of an element relate to its absorption spectrum and what does this tell us?
\* The coloured areas on the emission spectrum will be blacked out on the absorption spectrum and vice versa. \* This means that the wavelengths that are emitted are also the wavelengths that are absorbed.
149
SP6c - If an atom gains more energy than needed to just move an electron to another orbit, what can happen and what is this called?
\* The atom can lose an electron. \* This is called ionisation as the atom has become an ion
150
SP6c - What can happen if an atom gains enough energy and what does this create?
\* An electron can move to a higher orbit. \* When it returns back to its orbit it emits energy in the form of visible light. \* The wavelength (and therefore colour) depends on the change in orbit.
151
SP6c - What do we call radiation that causes an atom to lose an electron?
Ionising radiation
152
SP6c - What do we use to see the light produced by an atom?
\* An emission spectrum. \* A black line spectrum with coloured lines along it displaying which wavelengths were emitted.
153
SP6c - What is an ion?
An atom that is charged due to a gain or loss of electrons.
154
SP6d - Before measuring the radioactivity of a source what must be done?
\* Measure the background radiation so you can take this away from the radiation that you measure or else you value will be the source's radiation + the background radiation.
155
SP6d - What are the six main sources of background radiation
\* Medical \* Ground and buildings \* Food and drink \* Radon gas \* Cosmic rays \* Nucelar
156
SP6d - What are ways of measuring radioactivity?
\* With a Geiger Mueller tube / counter Meausres the count rate \* Photographic film (badges called dosimeters) Gets darker / changes colour as its exposed to more radioactivity
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SP6d - What is background radiation?
Radiation that is constantly all around us at a safe level.
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SP6d - Which source of backgrond radiation accounts for most of it and approximately how much is it?
Radon gas just under 50%
159
SP6e - Rank and explain the types of radiation in terms of ionisation.
\* Alpha (Most) \* Beta (+/-) \* Gamma (Least) Since alpha particles are emitted at high speeds thay carry most energy and are best at ionistation.This is the opposite for Gamma.
160
SP6e - Rank the types of radiation in terms of penetration / range.
\* Gamma (Most) \* Beta (+/-) \* Alpha (Least)
161
SP6e - What does it take to stop each type of radiation?
\* Alpha: paper/skin/few cm of air \* Beta: few m of air/3mm of alluminium \* Gamma: few Km of air/ few cm of lead/ several m of concrete
162
SP6e - What don't gamma rays have that other radiation does.
Since it is an EM wave and not a particle, it doesn't have a charge.
163
SP6e - What is a beta minus particle?
An electron
164
SP6e - What is a beta plus particle?
A positron (A positive electron)
165
SP6e - What is an alpha particle?
A helium nucleus consisting of 2 protons and 2 neutrons
166
SP6f - What occurs in alpha decay?
An unstable nucleus looes 2 protons and 2 neutrons (an alpha particle) causing its mass number to decrease by 4 and its atomic number to decrease by 2.
167
SP6f - What occurs in beta minus decay?
\* A neutron decays into a proton and a high energy electron.
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SP6f - What occurs in beta plus decay?
\* A proton decays into a neutron and a high energy positron.
169
SP6f - What occurs in gamma decay?
An unstable nucleus emits a gamma ray becoming more stable.
170
SP6g - If a substance has a half-life of 2 minutes and has a count rate of 128Bq, what will its count rate be after 8 minutes?
8/2 = 424 = 16128/16 = 88Bq
171
SP6g - What is a half-life?
\* The time it takes for half the unstable nuclei of a substance to decay \* The time it takes for the count rate of a radioactive substance to decrease by half.
172
SP6h - How may radioactivity be used when a pipe leaks?
\* A gamma source is added to water and passed through the pipe and a geiger tube is placed on top. \* Areas with leaks have higher levels of radiation.
173
SP6h - How might radioactivity be used in hospitals?
\* To detect and treat cancer (radiotherapy and PET scans) \* To sterelise equipment
174
SP6h - How might you use radiation to treat food?
Irradiating fresh produce makes it safer to eat and increases its life time.
175
SP6h - When making paper, how may radioactivity be used?
\* A beta source is placed on one side of the paper and a detector on the other. \* When the detector detects too many beta particles passing through, the paper is too thin and so reduces the force applied to the paper, increasing thickness \* Whereas, if the paper is too thick, the opposite happens.
176
SP6i - What are the 4 ways medical staff reduce their exposure to radioactive sources?
\* Increasing their distance from the source \* Shielding the source \* Minimising time spent near the source \* Wearing dosimeter badges to monitor exposure
177
SP6i - How may a nuclear accident affect food supply?
\* Water and soil nearby gets contaminated which contaminates the crops and plants. \* Animals that feed on this also become contaminated,
178
SP6i - How may someone hande radioactive sources safely?
\* Using tongs \* Not pointing the source at people \* Storing the source in lead lined containers
179
SP6i - What is it called when the DNA inside a cell is damaged by ionising radiation?
Mutation
180
SP6i - What is the difference between irradiation and contamination?
A substance becomes irradiated if exposed to a radioactive source but is contaminated if it is still radioactive even when the source is taken away.
181
SP6i - What sort of sources are used when treating cancer patients?
Ones with short half - lives
182
SP6i - Why are medical radioactive sources made on site?
They have a short half life to reduce the time the patient is exposed to the radiation
183
SP6i - Why do mutations in cells have long term effects?
Because they can be passed down through generations
184
SP6j - How does a PET scan work?
\* A tracer that has beta plus decay is injected into the patient. \* When the emitted positron meets an electron, they annihilate each other and release two gamma rays in opposited directions. \* The PET scanner moves around the patient detecting where gamma radiation originates from forming a series of images.
185
SP6j - How may a gamma camera be used in medical diagnosis?
\* A radioactive tracer with a short half - life is injected into the blood stream. \* The gamma camer detects areas of high radiation. \* This can help in diagnosing internal bleeding. \* The tracer is made using radioactive glucose molecules because cancer cells take up glucose quickly.
186
SP6j - What is external radiotherapy?
Several beams of gamma rays, X-rays or protons are fired at the tumour from multiple directions.
187
SP6j - What is internal radiotherapy?
This is when a beta emitter is placed inside the body, within or very close to the tumour.
188
SP6j - Why is internal radiotherapy more advantageous?
\* It is targetted at the tumor, meaning healthy cells are mostly left unharmed
189
SP6k - What are the pros and cons of using nuclear energy over fossil fuels to generate energy?
Pros: \* Sources of uranium will take a long time to expire \* They store more energy per kg \* They cause less deaths \* The stations themselves don't release GH gases Cons: \* The extraction process release many GH gases \* Waste substances can contaminate environment if not stored properly \* Very expensive to decomission safely \* Nuclear accidents cause many deaths and long term effects
190
SP6l - How does the energy generated fin a nuclear reactor get transferred into electrical energy?
\* Thermal energy is generated from the reaction process. \* This is used to heat up a source of water turning it into steam. \* This steam turns turbines which turn and power the generator generating electricity.
191
SP6l - If the neutrons released by nuclear fission go on to cause another nucleus to decay, what is this called?If this isn't controlled, what can this lead to?
A chain reaction A nuclear explosion
192
SP6l - What are the jobs of the moderator and the control rods in a a reactor?
Control Rods: They absorb neutrons to control the fission chain reaction. If the temperature is too high, we lower the control rod so it can absorb more neutrons and reduce fission reaction. If the temperature is too low, we raise the control rods so it can absorb less neutrons and increase the fission rate. Moderators: Material which slows down neutrons. This allows the neutrons to be absorbed by the fuel easily.
193
SP6l - What are fuel rods?
Fuel rods contain uranium and undergo fission so thermal energy is released
194
SP6l - What is nuclear fission?
When an unstable nucleus absorbs a neutron, it decays releasing two smaller daughter nuclei, neutrons and energy.
195
SP6l / SP6mCompare and Contrast Nuclear Fission and Fusion
Similarities Fission and Fusion both release large amounts of energy during the reaction Differences Fission is the splitting of a nuclei into 2 daughter nuclei whereas fusion is the joining of smaller nuclei to form a larger nuclei. Fission can cause chain reactions and are used in power stations whereas the conditions required for fusion to occur are near impossible to produce in a power station.
196
SP6m - What conditions are needed for nuclear fusion to occur and why?
\* Nuclear fusion requires that the nuclei are travelling at over 1,000,000 m/s and in temperatures hotter than the sun. \* This is to overcome the electrostatic repulsion that would otherwise repel the two like charged nuclei away from each other.
197
SP6m - What is nuclear fusion and where does it take place?
Nuclear fusion occurs when two smaller nuclei (typically hydrogen) join together to form a larger atom (helium) and energy in the form of gamma radiation
198
SP6m - Why aren't there any working nuclear fusion stations?
To maintain conditions required to overcome elctrostatic repulsion is extremely costly and hard to sustain on earth.
199
SP7a - What developments in techonology have allowed us to make more detailed observations?
\* Computers allow detailed analysis. \* Photography allows accurate and permanent storage of events. \* Telescopes can now be place outside of the earth's atmosphere giving wider and more detailed detection. \* Space probes allow better analysis of the solar system.
200
SP7a - What is the geocentric model?
The model of our solar system in which everything orbits the earth.
201
SP7a - What is the heliocentric model?
The current model of our solar system where the sun is at the centre and other planes orbit it.
202
SP7a - Who came up with Geocentric Model?
Ptolemy
203
SP7a - Who came up with Heliocentric Model?
Copernicus
204
SP7a - Why are telescopes place outside the earth's atmosphere more detailed than a regular telescope?
\* The earth's atmosphere absorbs many waves of the EM spectrum. \* Outside the atmosphere, these could be detected. (such as infrared radiation) \* Clouds and dust in the air do not interfere with the image
205
SP7a - What shape is the earth's orbit around the sun?
Elliptical
206
SP7b - A satellite in which type of orbit is used for communication with parts of the earth near the poles?
Highly elliptical orbits
207
SP7b - A satellite in which type of orbit needs the least fuel for launching?
Low earth orbits
208
SP7b - A satellite in which type of orbit will eventually pass over all parts of the earth?
Polar orbits
209
SP7b - At what angle is the force between the earth and satellite?
90°
210
SP7b - Explain the speeds that a satellite would have to be travelling at in relation to its orbit, and the changes in orbit it would experience if it changed speed.
\* The gravitational force on an object in a lower orbit is a stronger than at a higher orbit so a satellite at a lower orbit would have to travel at a higher speed to stay in orbit. \* Once it eventually slows down, it will drop towards earth. \* However as it drops it gains speed and will eventually be able to be at a lower orbit at a faster speed. \* Once it drops enough that it passes through the earth's atmosphere, the air resistance will slow it down and it will eventually fall to earth.
211
SP7b - What are the four types of orbits for artificial satellites?
\* Highly elliptical \* Circular geostationary \* Low earth orbits \* Polar orbits
212
SP7b - What is a geostationary orbit and what are these satellites used for?
\* Satellites that stay in the same place relative to the earth's position. \* They move at 3070 m/s and are used for broadcasting.
213
SP7b - What is the difference between weight and mass?
Your weight is the force acting on you dependant on your mass and the gravitational field strength.
214
SP7b - What is the gravitational field strength on earth?
9.81 N/Kg(Can be rounded to 10N/Kg)
215
SP7b - What reaction takes place inside a star?
Nuclear fusion(typically H + H = He)
216
SP7b - Why doesn't a satellite continue moving in a straight line?
The gravitational force between the earth and the satellite causes it to continuously change direction and orbit the earth.
217
SP7b - Describe the life cycle of a star much larger than our sun. [6 Marks]
It starts with a Nebula (A cloud of gas and gases). The materials are pulled together by their own gravity, becoming denser until their own gravtitational pull causes it to collapse in on itself forming a protostar. Eventually the pressure and temperature in the protostar become large enough that nuclear fusion starts to occur converting hydrogen to helium The energy released form the fusion reactions push the star outward causing it to expand. Once the force of the gravity pulling the star inwards matches the force of pressure from the fusion reactions, the star will be at a steady size and in its main sequence stage where it continues to convert hydrogen to helium Eventually, hydrogen runs out and heavier reactions take place. This creates more energy which expands the star more forming a red supergiant. These heavier fusions are carried out all the way to iron when it runs out of fuel. The star rapidly collapses causing a supernova This leaves behind a very dense neutron star If the mass of the star is even larger, then a black hole is formed in place of the neutron star.
218
SP7b - Describe the life cycle of a star the size of our sun. [6 Marks](write this down)
\* It starts with a Nebula (A cloud of gas). \* The particles in this pull themselves together, becoming denser until their own gravity causes it to collapse in on itself forming a protostar. \* Eventually the pressure and temperature in the protostar become large enough that nuclear fusion starts to occur converting hydrogen to helium \* The energy released form the fusion reactions push the star outward causing it to expand. \* Once the force of the gravity pulling the star inwards matches the force of pressure from the fusion reactions, the star will be at a steady size and in its main sequence stage where it continues to convert hydrogen to helium \* Eventually, hydrogen runs out and heavier reactions take place. \* This creates more energy which expands the star more \* The outermost layers are no longer held in place by the force of gravity so they expand forming a red giant \* Once all the fuel has run out, all the layers disband forming a shell of gas. \* This leaves behind a highly dense white dwarf which doesn't carry out any reactions.
219
SP7d - What do we use to check red-shift?
Absorption spectrums of the galaxy compared to the absorption spectrum of the sun.
220
SP7d - What does it mean if one galaxy has a greater red-shift than another?
That galaxy is further away and moving faster than the other.
221
SP7d - What is red-shift?
When light form distant galaxies shift towards the red side of the spectrum due to wavelengths being stretched as the galaxy moves away from earth.
222
SP7d - What is the doppler effect?
When the pitch of a noise get lower as it travels aways from you. (and higher when it travels towards you)
223
SP7d - Why does the doppler effect occur?
As a sound travels, the wavelengths are squashed or stretched meaning the sound's pitch appears higher or lower.
224
SP7e - What are the two main theories for the origin of the universe?
\* The big bang theory \* Steady state theory
225
SP7e - What can we use as a model of why CMBR proves The Big Bang Theory?
\* A Currant bun has currants close together. \* As the dough rises, the number of currants stay the same but they are found at consistent rate throughout the bun.
226
SP7e - What is the Big Bang Theory?
\* This theory states that the Universe began 13.8 billion years as a tiny particles and expanded from that point and is still expanding today.
227
SP7e - What is the Steady State Theory?
\* The universe always existed and as it expands as matter is continuosly created.
228
SP7e - What provides evidence for both theories of the universe and why?
Red-shift; as galaxies are constantly moving away the universe is constantly expanding.
229
SP7e - What provides evidence for the currently accepted theory?
It is thought that gamma radiation was released in the Big Bang.Due to the expanding universe, the wavelength of this radiation has increased, resulting in the microwave radiation present today
230
SP7e - Which theory of the universe is the currently accepted theory?
The Big Bang Theory
