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P1 Flashcards
Flashcards do conjunto (151)
- 1What are the 3 main ways of heat transfer?Convection, conduction & radiation
- 2What happens if there is a bigger temperature difference between an object and its surroundings?The heat transfer is quicker
- 3Describe a solid using kinetic theory- strong forces of attraction
- hold particles in fixed position
- regular arrangement
- little energy
- only vibrate - 4Describe a liquid using kinetic theory- weaker forces of attraction
- particles are close but can move
- some energy
- move in random directions at low speed
- fit base of container - 5Describe a gas using kinetic theory- hardly any forces of attraction
- free to move
- most energy
- move in random directions at high speed
- fit container - 6What effect on particles does heat have?Gives them more kinetic energy
- 7What do all objects do? (radiation)Emit and absorb infrared radiation from surface
- 8How does the heat of an object affect radiation?- an object hotter than its surroundings emits more radiation than it absorbs & VICE VERSA
- hotter = more radiation emitted - 9How does the surface/colour of an object affect radiation?- dark/matt objects emit and absorb more radiation
- light/shiny objects reflect more radiation - 10Where does conduction mainly occur and how does it work?In solids
Vibrating particles pass on extra kinetic energy to neighbouring particles - 11What effect does the density of the solid have on conduction and why?The denser the solid, the quicker the conduction
Particles are closer together so will collide more often and pass on energy - 12How is heat carried in metals?Free electrons colliding
- 13Are metals good conductors and why?Yes because the electrons are free to move and pass on energy quickly
- 14Where does convection mainly occur?Liquids and gases
- 15What is convection?When more energetic particles move from the hotter region to the cooler region - and take their heat energy with them
- 16Why can't convection happen in solids?The particles can't move
- 17How does convection work?1. particles get heated and gain energy
2. liquid expands, becomes less dense and rises
3. fast particles collide with slow and transfer heat
4. water cools, becomes more dense and sinks
5. creating a convection current - 18Why are convection currents made?Due to changes in density
- 19What is condensation?When a gas turns to a liquid
- 20How does condensation work?Particles cool, slow down and lose kinetic energy
Attraction forces between particles pull them together
Gas becomes liquid - 21How does water vapour condense?When it comes into contact with a cold surface
- 22What factors speed up condensation?- if the temp of gas is lower
- if the temp of surface gas touches is lower
- if density is higher
- if air flow is less - 23What is evaporation?When a liquid turns to a gas
- 24How does evaporation work?Particles at the surface escape if they are travelling in the right direction & have enough kinetic energy
Fastest particles escape so average speed and energy decreases and liquid cools e.g. sweat - 25What factors speed up evaporation?- if the liquid temp is higher
- if the density is lower
- if the surface area is larger
- if airflow over the liquid is greater - 26What factors affect the rate of heat transfer?- surface area (higher increases rate)
- material (conductor increases rate)
- objects in contact (conductor increases rate) - 27How do humans/animals control heat transfer?- adapted surface area e.g. ear size
- hairs stand up to trap layer of insulating air to reduce convection
- body diverts blood to surface when warm to increase heat loss by radiation - 28What is the equation for payback time?Payback time = cost ÷ annual saving
- 29What methods of saving energy are the most effective?The ones with the biggest annual saving
- 30What methods of saving energy are the most cost-effective?The ones with the lowest pay back time
- 31What does the U Value tell us?The lower the U Value, the better the insulator
- 32Give 5 examples of ways to save energy in the home.- cavity wall insulation - foam in gap between bricks stops convection currents in gap, radiation across it & conduction
- loft insulation - stops conduction & convection
- draught excluders reduce convection
- curtains - reduce conduction
-double glazing - 33What is specific heat capacity?Tells you how much energy something can store
Amount of energy needed to raise temperature of 1kg by 1°C - 34Energy transferred = mass × specific heat capacity × temp change What are the units?Energy transferred = Joules (J)
Mass = kg
SHC = J/kg°C
Temp = °C - 35What does the specific heat capacity of water tell us?It has a high SHC so can store more heat energy and is harder to heat & cool
Transported in the home using central heating pipes. - 36Name the 9 types of energy.Kids Hate Learning GCSE Energy Names
Kinetic Heat Light Sound
Gravitational Potential Chemical
Electrical Elastic Potential Nuclear - 37What is kinetic energy?Anything that moves
- 38What is heat energy?Flows from hot objects
- 39What is light energy?From the sun, light bulbs etc
- 40What is gravitational potential energy?Possessed by anything that can fall
Form of stored energy - 41What is chemical energy?Possessed by foods, fuels, batteries etc
Form of stored energy - 42What is sound energy?From loudspeakers or anything noisy
- 43What is electrical energy?Whenever a current flows
- 44What is elastic potential energy?Stretched springs, elastic, rubber bands etc
Form of stored energy - 45What is nuclear energy?Released only from nuclear reactions
- 46What is conservation of energy?Energy can be transferred, stored or spread out/lost - but not created or destroyed
- 47What makes energy useful?When it can be converted from one form to another.
- 48Give an example of energy transfer.Falling object = gravitational potential energy into kinetic energy
Battery = chemical energy into electrical and heat energy
TV = electrical energy into light, sound and heat energy - 49What kind of diagram shows efficiency?Sankey diagrams
- 50Why are machines not 100% efficient?Some energy is always lost - usually as heat
- 51What is useful energy also known as?Concentrated energy
- 52What eventually happens to all energy?It ends up as heat and becomes less concentrated as it is transferred to cooler surroundings
- 53What is a heat exchanger and how do they work?Reduce the amount of energy wasted by a machine
Pump cool fluid through the escaping heat and use it for other purposes - 54Energy = power x time What are the units?Energy = kWh
Power = kW
Time = hours - 55What is a kilowatt-hour?The amount of electrical energy used by a 1kW appliance left on for 1 hour
- 56How can we calculate the cost of electricity?Cost = number of units x price per unit
- 57What is energy transferred also known as when calculating the cost of electricity?The number of units used
- 58What should you think about when comparing electrical equipment?Pros and cons
Which uses less energy?
Which is more cost effective?
Can it be used with limited electricity?
Environmental effects - 59How is standard living affected by access to electricity?- Developed countries have more access.
- Lights - useful & safe at night
- Fridges - keep food fresh & store vaccines
- Hospitals - x rays - without this diagnosis/treatment would be poor
- Communication - keep in touch/news - 60Name the 4 non-renewable energy sources.Coal
Oil
Natural Gas
Nuclear fuels - 61What are the pros/cons of non-renewable energy sources?+ provide most of our energy
- will one day run out
- damage environment - 62Name 8 renewable energy sources.- wind
waves
- tides
- hydroelectric
- solar
- geothermal
- food
- biofuels - 63What are the pros/cons of renewable energy sources?+ will never run out
+ do not damage environment AS MUCH
- do not provide as much energy
- some are unreliable - depend on weather - 64How do power stations turn non-renewable energy sources into electricity?1. fossil fuel is burned to convert stored chemical energy into heat energy
2. heat energy used to heat water to produce steam
3. steam turns turbine converting heat energy to kinetic energy
4. turbine connected to generator - kinetic energy into electrical energy - 65How do nuclear power stations produce electricity?Same as normal power stations but use nuclear fission of uranium or plutonium to produce heat to make steam
Takes a long time - 66What is wind power and how does it produce electricity?Turbine are put in exposed places like on moors/coasts
Wind turns blades to power a generator to produce electricity - 67What are the pros and cons of wind power?+ no pollution
+ no fuel/minimal running costs
+ no permanent damage to landscape
- spoil view
- noisy
- dependent on wind
- expensive - 68What are solar cells and how do they produce electricity?Generate electric currents directly from sun light.
- 69What are the pros and cons of solar cells?+ no pollution
+ reliable
+ no running costs
- lots of energy to manufacture
- dependent on sunlight (only in daytime)
- expensive
- generate on small scale (e.g. 1 house) - 70What is hydroelectric power and how does it produce electricity?1. valley floods by building a big dam
2. water released to spin turbine
3. spins generator to produce electricity - 71What are the pros and cons of hydroelectric power?+ no pollution
+ immediate response to demand
+ reliable
+ no fuel / low running costs
- valley is flooded / loss of habitat
- ugly when reservoir dries up
- expensive - 72What is pumped storage and how does it produce electricity?Extra electricity at night is used to pump water to a higher reservoir and can be released quickly at peak demand e.g. around 5/6pm
Same as hydroelectric but only stores energy - nothing is generated - 73What are waves and how do they produce electricity?Small wave-powered turbines on the coast
Waves move up and down to force air into turbine and drives the generator - 74What are the pros and cons of waves?+ no pollution
+ no fuel / low running costs
- spoil view
- hazard to boats
- fairly unreliable
- expensive
- used on a small scale - 75What are tidal barrages and how do they produce electricity?Dams built across river estuaries with turbines in them.
Tide comes in, estuary fills up & drives turbines
Water is let through turbine at a controlled speed
Energy source = gravity from sun/moon - 76What are the pros and cons of tidal barrages?+ no pollution
+ fairly reliable
+ good for storing energy
+ no fuel costs / low running costs
- expensive
- prevents free access by boats
- spoils view / changes habitats
- tide height can vary - 77What is geothermal energy and how does it produce electricity?Heat from underground. Only possible near volcanic areas
Source of heat = slow decay of radioactive elements inside Earth
Steam / hot water rise to surface & spin a turbine to drive a generator - 78What are the pros and cons of geothermal energy?+ no environmental issues
- expensive (not cost effective)
- few suitable locations - 79What are biofuels and how do they produce electricity?Made from dead organisms/plants/waste e.g. straw or ethanol.
Burnt to heat water to produce steam to spin a turbine and drive a generator. - 80What do all fossil fuels release when burned and what is the environmental consequence of this?CO2
Adds to greenhouse effect and contributes to global warming - 81What does burning coal and oil release and what does this cause?Sulfur dioxide
Causes acid rain (harmful to environment)
Can be reduced by removing sulphur before fuel is burned or cleaning up the emissions - 82What is a problem of coal mining?Makes a mess of landscape
- 83What is a problem with using oil as an energy source?Oil spillages cause serious environmental problems
- affect aquatic mammals and birds - 84What are the problems with using nuclear fuel?- waste is dangerous and hard to dispose
- fuel is cheap but overall cost is high due to cost of power plant
- very risk e.g. Chernobyl disaster - 85What are the pros and cons of using biofuels?+ quick
+ natural
+ carbon neutral
- huge land areas needed = loss of habitat
- decay & burning increases CO2 & methane emissions - 86What is carbon capture and storage (CCS)?Used to reduce amount of CO2 building up in atmosphere and reduce strength of greenhouse effect
Collects CO2 from power stations before it is released into atmosphere. It is stored in empty gas & oil fields under sea - 87What should be considered when comparing energy resources?- set up time
- set up costs
- running costs
- reliability
- location
- environmental impacts - 88What is the National Grid?A network of power lines
Takes electrical energy from power stations to homes/industry - 89What is needed on the National Grid to transmit lots of power?A high voltage or a high current
High current = lots of energy lost
Cheaper to increase voltage to 400000V - 90How is voltage stepped up/down on the National Grid?- step up transformers increase voltage for efficient transmission
- step down transformers decrease voltage to safe usable levels - 91What are the pros and cons of overhead cables?+ low set up cost
+ easy to access faults
+ minimal disturbance to land
+ easy to set up
- requires lots of maintenance
- ugly
- affected by weather
- less reliable - 92What are the pros and cons of underground cables?+ little maintenance
+ hidden
+ not affected by weather
+ more reliable
- high set up cost
- hard to access faults
- hard to set up
- lots of disturbance to land - 93What is supply and demand and how is it dealt with?Energy demands increasing
Supply increased by opening more power plants or increasing their output
Demand reduced by using energy efficient appliances and being careful about waste - 94Draw and label a wave.
- 95What is frequency of a wave? What is the unit?The number of waves per second
Hz - 96Speed = Frequency x Wavelength What are the units?speed = m/s
frequency = Hz
wavelength = m - 97What is amplitude?Distance from rest position to a peak.
- 98Draw a transverse wave.
- 99Give an example of a transverse wave.Most waves
- light
- EM waves - 100What direction are the oscillations/vibrations on a transverse wave?Perpendicular to the direction of energy transfer
eg. up and down - 101Draw a longitudinal wave.
- 102What is a wavelength of a longitudinal wave?From the start of a compression to the end of a rarefaction
- 103Give an example of a longitudinal wave.Sound
Seismic waves - 104What direction are the oscillations/vibrations on a longitudinal wave?Parallel to the direction of energy transfer
- 105What 3 processes can happen to all waves? When do these happen?They can be reflected, refracted and diffracted
When the wave arrives at an obstacle or different medium - 106What happens if light travelling in the same direction reflects from an uneven surface?Light reflects off at different angles
- 107What happens if light travelling in the same direction reflects from a smooth, even surface?Light is reflected at the same angle and the reflection is clear
- 108What is the law of reflection that applies to every reflected ray?Angle of incidence = angle of reflection
- 109Draw a reflection on a plane mirror.
- 110Draw a ray diagram of how an image is formed in a plane mirror.
- 111What is important to remember when drawing a ray diagram for a plane mirror?- image is same size as object
- image is as far behind mirror as object is in front
- image is virtual and upright
- image is laterally inverted - 112What is diffraction?When waves spread out as they pass through a gap or around an obstacle
- 113What does the amount of diffraction depend on?The size of the gap relative to the wavelength of the wave
- 114What happens if the gap is much wider than the wavelength?There is little diffraction
- 115What happens if the gap is a bit wider than the wavelength?Diffraction occurs at the edges of the wave
- 116What happens if the gap is the same as or narrower than the wavelength?There is maximum diffraction
- 117What is refraction?When a wave crosses a boundary between 2 mediums and it changes direction
- 118What happens if a wave hits a different medium 'face on' (along the normal)?Change in speed
No change in direction - 119What happens if a wave hits a different medium at an angle?Wave changes speed and direction (refracts)
- 120Draw a light ray travelling from air to glass to air.
- 121What are EM waves?Electromagnetic waves that have a continuous spectrum
- 122Name the 7 types of EM waves in order of decreasing wavelength.Radio waves
Microwaves
Infrared radiation
Visible light
Ultra violet
X-rays
Gamma rays - 123What effect does decreasing wavelength have on the EM waves?Increasing frequency and energy
- 124Name the spectrum of visible light in order of decreasing wavelength.Red
Orange
Yellow
Green
Blue
Indigo
Violet - 125What speed do EM waves travel at in a vacuum?3 x 10^8 m/s
- 126What are radio waves?EM waves with wavelengths longer than 10cm
- 127What are radio waves mainly used for?Communication
- 128What is the difference between short wave signals and long wave radio?Short wave signals - reflect off ionosphere - must be within direct sight of transmitter to receive
Long wave radio - long wavelengths diffract (bend) around curved surface of earth - can be transmitted across the world - 129What is the ionosphere?An electrically charged layer in the Earth's upper atmosphere
- 130What are microwaves often used for? Why?Satellite communication eg satellite TV
Wave has to pass through Earth's watery atmosphere - 131How does satellite communication work?Signal from transmitter transmitted into space
Picked up by satellite's receiver dish orbiting above earth
Transmits signal back to earth in different direction & received by satellite dish - 132Give the 2 uses of infrared waves and how they work.- Remote controls - emit patterns of infrared waves to send different commands to appliance
- Optical fibres - carry signals through fibres as they are reflected off the sides - 133What is visible light often used for?Photography/Cameras
- 134How are sound waves caused?By vibrations passed through the surrounding medium as a series of compressions
- 135Where does sound travel quickest?Solids
- 136Why can sound not be heard in space?No particles for waves to travel
- 137What is a kHz? What is a mHz1000Hz
1000000Hz - 138What is a reflected sound wave called? Why is there a delay?An echo
It has to travel further to be reflected by hard surface - 139How are reflected sound waves quickly absorbed?Objects like furniture, carpet and curtains
- 140When do sound waves refract?When entering a different medium e.g. air to water
- 141What is the doppler effect?A change in frequency of sound wave around a moving source.
Moving towards you = frequency is higher, wavelength is shorter & pitch is higher
Moving away from you = frequency is lower, wavelength is longer & pitch is lower - 142Does the doppler effect occur on stationary objects?No because the sound waves are evenly spaced
- 143What is red shift?An observed increase in wavelength of light from distant galaxies
- 144How does red shift happen?As a galaxy moves away from us, light waves get stretched making it appear more red.
Amount of red shift tells us how far away it is and how quickly it is moving. - 145How does blue shift happen?As a galaxy moves towards us, light waves get squashed making it appear more blue.
Amount of blue shift tells us how close it is and how quickly it is moving. - 146The further away the galaxy......the greater the red shift
They are moving away faster than closer ones - 147What is red shift used as evidence for?The Big Bang Theory
- 148How do scientists think the universe began?The Big Bang Theory
14 billion years ago, all matter/energy was compressed into a tiny space, exploded and began expanding
Still expanding today - 149What is the 'Steady State' theory?That the universe has always existed as it is now and always will do
Not the most likely explanation - 150What is Cosmic Microwave Background Radiation (CMBR)?Low frequency electromagnetic radiation coming from all parts of the universe
- 151How does the Big Bang Theory explain CMBR?Just after Big Bang when universe was still hot, everything emitted high frequency radiation
Universe expanded and cooled and frequency dropped
Now seen as microwave radiation
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- GCSE GCSE Physics (Physics 1) FlashCards sobre P1 Flashcards, criado por Charlotte Buckley em 10-03-2016.
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- Charlotte Buckley
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