P1 - Q&A Cards

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What does Heat Radiation flow away from?
A hotter object to it's cooler surroundings
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What is Heat Radiation?
The transfer of energy by Infrared radiation
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How does the heat of an object affect the emission of Infrared Radiation?
An object that's hotter than it's surroundings emits more radiation that it absorbs. The hotter an object is, the more radiation it radiates in a given time
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What Surface colour and Texture is the best at emitting and absorbing Infrared radiation?
Dark, Matt surfaces
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Why are light, shiny surfaces not good at absorbing and emitting Infrared Radiation?
They reflect the Infrared radiation falling on them
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What does the Kinetic Theory explain?
How particles move in solids, liquids and gases
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What is the energy that an object or particle has due to it's movement called?
Kinetic energy
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What are the 3 states of matter?
Solid, Liquid and Gas
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What is the arrangement of particles in Solids and why?
They are in a fixed, regular arrangement becuase strong forces of attraction hold the particles close together
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What is the energy in solid particles like and how does this affect their movement?
The particles have little energy so they can only vibrate about their fixed positions
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What is the arrangement of particles in Liquids and why?
The particles are close together but can move past each other and form irregular arrangements. This is because there are weaker forces of attraction between the particles
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What is the energy in liquid particles like and how does this affect their movement?
They have more energy than solid particles and move in random directions at low speeds
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What is the arrangement of particles in Gases and why?
The particles are free to move everywhere becuase there are almost no forces of attraction between the particles
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What is the energy in gas particles like and how does this affect their movement?
The particles have more energy than those in liquids and solids and travel in random directions at high speeds
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What is Conduction of heat energy?
The process where vibrating particles pass on their extra kinetic energy to neighbouring particles
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What does Heat Conduction cause?
A rise in temperature at the other end of the solid that is being heated. Hence, increasing the heat radiating from it's surface
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Why is Heat Conduction faster in denser solids?
Because the particles are closer together and so collide more often and pass energy on
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Why are metals the best at conducting heat?
Because they have free electrons which can move quickly and collide with more particles faster, passing on more energy
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What is an Insulator?
A material that has large spaces between its particles and therefore conduct heat energy very slowly
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What is Convection?
When the more energetic particles move from the hotter egion to the cooler region and take their heat energy with them
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In what states of matter can convection occur and why?
In gases and Liquids because they are free to move about
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Which process is more effective between Conduction and Convection?
Convection
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Why can't convection happen in solids?
Because the particles cannot move
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What are Convection currents based on?
Changes in Density
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In convetion, wy does hot water rise?
Because it is less dense
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What form of heat transfer is used with Radiators?
Convection currents
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How does a Radiator Heat up a room?
Hot, less dense air by the radiator rises and the fast moving particles collide with slow moving particles and transfer heat. The particles cool and become more dense and sink. This forms a current which eventually heats the room
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What happens to particles when they cool?
They slow down and lose kinetic energy
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What is condensation?
When a Gas cools and the attractive forces between the particles pull them closer together to become a liquid
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What is Evaporation?
When a liquid is heated and the particles gain kinetic energy and are fast enough to overcome the attractive forces of the other particles, they then can escape as a gas
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When a liquid is evaporating, why does the temperature fall?
Because the average speed and kinetic energy of the remaining particles that haven't yet evaporated decreases
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What 4 factors increase the rate of Evaporation?
1. Higher temperature 2. Lower Density 3. Larger Surface area 4. Greater airflow over the liquid
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What 4 factors increase the rate of Condensation?
1. Lower temperatures 2. Less airflow 3. Lower temperature of the surface the gas touches 4. Higher density
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How and why does surface area affect the rate of heat transfer?
The bigger the surface area, the more infrared waves tha can be emitted or absorbed by the surface, so the quicker the transfer of heat
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How and why does volume affect the rate of heat transfer?
An object with a smaller volume will cool more quickly as a higher proportion of the object will be in contact with it's surroundings
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Which type of materials are best at transferring heat?
Objects made from good conductors
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What 4 factors in a Vacuum flask minimise heat transfer?
1. Double-walled with a vacuum inbetween 2. Walls are silvered 3. Insulating foam 4. Stopper is plastic and filled with cork
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What heat transfer do the silvered walls in a vacuum flask minimise?
Radiation
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What heat transfer does the Insulating foam in a vacuum flask minimise?
Conduction
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How does the body limit the amount of heat lost by convection?
In cold, hairs stand up to trap a thick layyer of insulating air around the body
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How does the body increase the amount of heat lost by Radiation?
In heat, more blood is diverted near the surface of the skin
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What attribute do animals in warm climates have to help control heat transfer?
The have larger ears to increase the surface area
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What are 5 ways of increasing energy efficiency in the home?
1. Loft insulation 2. Hot water tank jacket 3. Double glazing 4. Draught-proofing 5. Cavity wall insulation
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What is the eqution for Payback time?
Initial cost / Annual saving
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What does U-Value show?
How fast heat can transfer through a material
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What is the difference between a high U-Value and a low U-Value?
Heat transfers faster through materials with higher U-Values
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What has a low U-Value?
Insulating material
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What is specific heat capacity?
The amount of energy needed to raise the temperature of 1kg by 1°C
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What is the measure of how much energy a substance can store?
It's specific heat capacity
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Why does it take more heat energy to increase the temperature of some materials than others?
Materials need which need to gain lots of energy to heat up also release loads when they cool down again. They can store a lot of heat. This specific heat capacity is different in different materials
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What is the equation for enegy transferred (and specific heat capacity)?
Energy transferred = mass x specific heat capacity x temperature change
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What are the 9 forms of energy transfer?
1. Electrical 2. Light 3. Sound 4. Kinetic 5. Nuclear 6. Thermal 7. Gravitational Potential 8. Elastic potential 9. Chemical
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Where do we find Electrical energy?
Whenever a current flows
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Where do we find light energy?
From the sun, light bulbs etc
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Where do we find Sound energy?
From loudspeakers or anything noisy
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Where do we find kinetic energy?
Anything that's moving has it
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Where do we find Nuclear energy?
released only from nuclear reactions
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Where do we find thermal energy?
Flows from hot objects to cold ones
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Where do we find gravitational potential energy?
In anything that can fall
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Where do we find Elastic potential energy?
In stretched springs or rubber bands etc
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Where do we find Chemical energy?
In foods, fuels and batteries
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What energy types are forms of stored energy and why?
Gravitational potential, Elastic potential and chemical energy - they're not doing anything, only waiting to happen
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What is the rule for energy transfer?
Energy can be transferred usefully from one form to another, stored or dissipated - but it can never be created or destroyed
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When is energy only useful?
When it can be converted from one form to another
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Why are useful devices useful?
Because they can transform energy from one form to another
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What happens to some input energy in machines?
Some is always lost or wasted
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What makes a machine efficient?
The less energy that it wastes
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What is the equation for efficiency?
Efficiency = Useful Energy out / Total Energy In
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What is wasted energy usually spread out as?
Heat
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What will no device ever be?
100% efficient
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What happens to wasted energy?
As the heat is transferred to cooler surroundings, the energy becomes less concentrated - it dissipates
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What do Sankey diagrams show?
How much of the total energy input is being usefully used and how much is wasted
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What dies the thickness of the arrow in Sankey diagrams represent?
The thicker the arrow, the more energy it represents
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What is a Kilowatt hour?
The amount of electrical energy used by a 1Kw appliance left on for 1 hour
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What is the unit for specigc heat capacity?
J/Kg°C
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What is the unit for kilowatt hours?
Kwh
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How do we work out the cost of electricity?
Cost = Units x Price
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What are the 4 non renewable energy resources?
1. Coal 2. Oil 3. Gas 4. Nuclear fuels (Uranium + Plutonium)
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What provides us with most of our energy?
Fossil fuels and Nuclear fuels
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What are the 8 types of renewable energy sources?
1. Wind 2. waves 3. Tides 4. Hydroelectric 5. Solar 6. Geothermal 7. Food 8. Biofuels
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Why are renewable energy sources worse than non renewable ones?
They don't provide much energy and some are unreliable as they depend on the weather
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What is Wind power and how does it work?
Putting lots of windmills on moors or coasts. The wind turns the blades, the blades turn a generator and electricity is produced
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What pollution is produced from Wind power?
No pollution except in manufacturing
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What are 3 disadvantages of Wind power?
1. Spoils the view 2. Very noisy 3. There's no power when the wind stops - not very reliable
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What are the costs of Wind Power?
The initial costs are high, but there are no fuel costs and minimal running costs
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What are 2 advantages of Wind power?
1. It's renewable 2. There's no permanent damage to the lanscape
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What are Solar cells and how do they work?
They generate electric currents directly from sunlight. They're generally used to power road signs and satelites
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What pollution is produced from Solar cells?
No pollution except a lot in manufacturing
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What are 2 disadvantages of Solar cells?
1. Only reliable when the sun is out 2. Not practical and too expensive to connect them to the Nationa grid
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What are the costs of Solar cells?
The Initial costs are high, But there are no fuel costs or running costs
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What are 2 advantages of Solar cells?
1. They are a renewable source of energy 2. They can be very reliable in sunny countries
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What is Hydroelectric power and how does it work?
It requires the flooding of a valley by building a dam. Rainwater is caught and allowed through turbines
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What pollution is produced from hydroelectric power?
No pollution but the manufacturing produces Methane and CO2
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What are 2 disadvantages of Hydroelectric power?
1. Possible loss of habitat where they are built 2. Only really useful on a small scale in remote areas
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What are the costs of Hydroelectric power?
The Inital costs are high, but there aren't any fuel costs and there are minimal running costs
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What are 3 advantages of Hydroelectic power?
1. It's renewable 2. It can provide immediate response to a demand 3. There's no problem with reliability except in drought (which is rare)
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How is Hydroelectric power a form of stored energy?
Water is pumped up to a higher reservoir, it gains gravitational potential energy which is a form of stored energy
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What is Wave power and how does it work?
It needs small wave-powered turbines around the coast. The waves provide an up and down motion to drive a generator
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What pollution is produced from Wave power?
There's no pollution!
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What are 4 disadvantages of Wave power?
1. It spoils the view 2. It's a hazard to boats 3. It's fairly unreliable - waves tend to die out when the wind drops 4. Only really useful on small islands
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What are the costs of Wave power?
The Initial costs are high but there are no fuel costs or running costs
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What are Tidal barrages and how do they work?
Big dams are built across river estuaries with turbines. The tide comes in, drives the turbines, and electricity is produced
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What pollution is produced from Tidal Barrages?
There is no pollution!
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What are 2 advantages of Tidal Barrages?
1. The source of energy is Gravity and the moon 2. Tides are pretty reliable and happen twice a day
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What are 3 disadvantages of Tidal Barrages?
1. They prevent access for boats 2. They alter the habitat of the wildlife 3. They don't work when the water level is the same on either side of the barrage
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What are the costs of Tidal barrages?
Initial costs are moderate and there are no fuel or running costs
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What is Geothermal energy and how does it work?
Steam and hot water from hot rocks drive a generator
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What are 2 advantages of Geothermal energy?
1. Brilliant free energy with no environmental problems 2. Can be used to heat buildings directly in some places
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What is a disadvantage of Geothermal energy?
It is only possible in volcanic areas with hot rocks so there aren't many suitable locations for the power plant
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What are the costs of Geothermal energy?
The cost of building it are high compared to the amount of energy we get out of it
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What are Biofuels and how are they used?
They're used like fossil fuels and can be used in cars
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Where can we get Biofuels from?
Organisms that are still alive or from dead organic matter
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What is are examples of where we can get a biofuel?
Crops like sugar cane can be fermented for Ethanol, or plant oils can be modified to produce Biodiesel
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What are Nuclear Reactors and how do they work?
Nuclear power stations are the same as fossil fuel power stations but with the nuclear fission of Uranium and Plutonium producing the heat to make steam and drive a turbine
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What are 4 disadvantages of Nuclear power stations?
1. They take the longest time off all power stations to start up and to decommission 2. Nuclear waste is dangerous and difficult to dispose of 3. There's risk of major catastrophe's like Chernobyl 1986 4. Uranium and Plutonium aren't renewable
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What are 2 advantages of Nuclear power stations?
1. They produce ALOT of energy 2. They are a very clean source of energy
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What is Carbon Capture used for?
To reduce the amount of CO2 buildng up in the atmosphere
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How does Carbon capture work?
By collecting CO2 from power stations before it is released into the atmosphere. The captured CO2 is then pumped into empty gas fields like those under the north sea
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What is the advantage of Carbon capture?
It is new technology that's developing quickly. It can be safely stored without adding to the greenhouse effect
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What is the difference in set up costs between Renewable and non renewable power stations?
Renewable stations are more expensive to set up
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What is the difference in reliability between Renewable and non renewable power stations?
Non renewable are all much more reliable
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What re the 3 main environmental issues surrounding energy resources?
1. Waste pollution 2. Reliant of other factors such as weather 3. Eyesore/ ruins environment
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What is the difference in running and fuel costs between Renewable and non renewable power stations?
Renewables have the lowest
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What is the location issue of certain power stations?
There are limited areas where particular stations can be built
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What does the National grid do?
It takes electrical energy from power stations to where it's needed in homes and industry
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What does the national grid need to transmit huge amounts of power?
Either high volatge or High current
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Why do we boost the volatge high and not the current when transmitting power through the national grid?
High current loses energy through heat in the cables and it's cheaper and more efficient to boost the voltage high and keep the current low
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What does the National grid require to transmit power at a high voltage?
It requires transformers to step up the voltage at one end for efficient transmission and then bring it back down to a safe, usable level at the other end
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What is the problem with supply and demand?
We need to generate and direct all the energy that the country needs and demands keep increasing. In the future energy supplies will need to increase or the demands need to decrease?
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How can we increase the supply of power?
By opening more power plants or increasing power output
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How can we decrease the demand for power?
Can be reduced by consumers using more energy efficient appliances
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What is the Wavelength?
The shortest distance between a point on a wave and the same point on the next wave (The distance from one peak to the next peak)
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What is the Frequency of a wave?
The number of waves passing a point per second
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What is the Amplitude?
The maximum height of the wave measured from the middle
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What is the equation for wave speed?
Wave speed = Frequency x Wavelength
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What do waves transfer?
Energy and information but without transferring matter
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How is energy transferred by waves?
By Oscillations (vibrations) in the material which the wave is travelling through
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What are Longitudinal waves?
Mechanical waves
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What are Transverse waves?
Electromagnetic waves
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What are 3 examples of transverse waves?
1. Electromagnetic waves 2. Ripples on water 3. A slinky waved up and down
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What are the vibrations like in Transverse waves?
Perpendicular to the direction of energy transfer of the wave
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What are 3 examples of longitudinal waves?
1. Sound waves 2. Shock waves 3. A pushed slinky
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What are the vibrations like in Longitudinal waves?
Parallel to the direction of enrgy transfer of the wave
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What do Longitudinal waves have that transfer energy?
Rarefractions and Compressions
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What allows us to see objects?
Reflection of light
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What is the law of reflection?
Angle of Incidence = Angle of Reflection
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What is the rule of the normal in reflection?
It is always perpendicular to the surace at the point of incidence
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What are 4 important points for ray diagrams?
1. The image is the same size as the object 2. It is as far behined the mirror as the object is in front 3. The image is virtual and upright 4.The image is laterally inverted - the left and right sides are swapped
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What happens to waves when they pass through a gap or pass an obstacle?
They spread out
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What does the amount of Diffraction depend on?
The size of the gap relative to the wavelength of the wave. The narrower the gap, or the longer the wavelength, the more the waves spread out
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What is a medium?
A material that a wave travels through
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What happens when waves go from one medium to another?
They can be refracted
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What happens to waves as they enter a different medium?
Their speed changes and this causes them to change direction
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How does a wave bend in refraction if it speeds up or slows down?
If it slows down, it bends towards the normal. If it speeds up, it bends away from the normal
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What happens if a wave travels along the normal in refraction?
Although the waves' speed changes, they don't change direction
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What are 3 facts about electromagnetic waves?
1. They are Transverse waves 2. They travel at the speed of light 3. They can travel through a vacuum
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What is the order from longest wavelength to shortest of the EM waves?
Radio waves, Microwaves, Infrared, Visible light, Ultra violet, X rays, Gamma rays
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What are the uses of Radio waves and why are they used for this?
They can diffract around hills and into tunnels. This makes it possible for radio signals to be recieved even if the reciever isn't in line of sight of the transmitter
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What are the dangers of Radio waves?
They don't have any!
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What are the uses of microwaves and why are they used for this?
Used for satellite communication and mobile phones. This is because their wavelength is short enough to penetrate the ionosphere and monitor things like oil spills, movement of icebergs etc
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What are the dangers of microwaves?
They can produce burns and cataracts and it is thought that they could infuence cancer
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What are the uses of Infrared waves?
Heating, cooking, remote controls, optical fibres and night vision
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How do remote controls with Infrared waves work?
They emitt diffrerent patterns of Infrared waves to send commands to an appliance
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What are optical fibres and how do they work?
They can carry data very quickly. The signal is carried as pulses of light and is reflected off the sides of a narrow core from one end of the fibre to the other
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What are the dangers of Infrared waves?
They can burn
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What are the uses of Visible light?
Seeing and photography
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What are the dangers of Visible light?
Eye damage from bright lights
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What are the uses of Ultraviolet light?
Discos, tanning salons and pollination
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What are the dangers of Ultraviolet light?
Skin cancers
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What are the uses of X rays?
Medical imagery and security
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What are the dangers of X rays?
Cancer
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What are the uses of Gamma rays?
Cancer treatment and observing the universe
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What are the dangers of Gamma rays?
Cancer
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What are sound waves caused by?
Vibrating objects
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What type of wave are sound waves?
Longitudinal
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How does a short sound wavelength affect it's frequency and pitch?
Short wavelength = high frequency = high pitch
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How does a long sound wavelength affect it's frequency and pitch?
Long wavelength = low frequency = low pitch
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How does the amplitude of a sound wave affect the volume?
The biggerthe amplitude, the louder the sound
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What is the doppler effect?
Relative velocity between the source and the observer
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Explain the Doppler effect
When a wave source approaches you, the wave you recieve will be higher in frequency and shorter in wavelength becuase the wave has compressed. So, the pitch will be higher
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What does each chemical elementthat absorbs different frequencies of light produce?
A specific pattern of dark lines at the frequencies that it absorbs in the visible spectrum
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What can we see when we look at light from different galaxies in terms of the patterns of dark lines?
We can see the same patterns but at slightly lower frequencies than they should be - they're shifted towards the red end of the spectrum
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What is red shift?
When the Pattern of dark lines that an element produces is shifted to a lower frequency, towards the red end of the spectrum
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What do measurments of red shift suggest?
That all the galaxies are moving away from us very quickly
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How does red shift vary for different galaxies?
More distant galaxies have greater red shifts than nearer ones
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What does red shift provide evidence for?
That the whole universe is expanding
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What does the Big bang theory state?
All thematter and energy in the universe must have been compressed into a very small space. Then it exploded from that single point and started expanding
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What does the Steady state Theory suggest?
That the universe has always existed as it is now and it always will. Based on the idea that the universe seems to be the same everywhere
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How does the Steady state theory explain the apparent expansion of the universe?
By suggesting that matter is being created in the spaces as the universe expands
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What is CMBR?
Cosmic microwave background radiation - low frequency electromagnetic radiation
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What is the only theory to explain CMBR and how does it?
The Big Bang theory. Just after the explosion, the universe was extremely hot, everything emitted very high frequency radiation, As the universe expanded, it cooled and the radiation dropped in frequency and is now CMBR
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What are 2 pieces of evidence for the Big Bang?
1. The firther away a galaxy is, the more it's light is red-shifted (The universe expands. The start of the universe was a single explosion) 2. CMBR (The remains of energy created just after the explosion)
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What are 3 of the big bang's limitations?
1. The rate of expansion is predicted to be slowing down but it's speeding up 2. No explanation for what caused the explosion 3. What the conditions were like before the explosion (or if ther was a before)
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Other cards in this set

Card 2

Front

What is Heat Radiation?

Back

The transfer of energy by Infrared radiation

Card 3

Front

How does the heat of an object affect the emission of Infrared Radiation?

Back

Preview of the front of card 3

Card 4

Front

What Surface colour and Texture is the best at emitting and absorbing Infrared radiation?

Back

Preview of the front of card 4

Card 5

Front

Why are light, shiny surfaces not good at absorbing and emitting Infrared Radiation?

Back

Preview of the front of card 5
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