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111 Cards in this Set

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What does infrared radiation involve?
Transfer of heat energy by electromagnetic radiation
What is infrared radiation also known as?
Thermal radiation
What do all objects emit and absorb?
Infrared radiation
What does the amount of infrared radiation given off depend on?
Surface
Shape
Dimensions
When will an object emit and absorb infrared radiation faster?
If there is a bigger difference in temperature between it and its surroundings
What are the characteristics of a dark, matt surface in terms of infrared radiation?
They emit and absorb more infrared radiation than light, shiny surfaces
What are the characteristics of a light, shiny surface in terms of infrared radiation?
Poor emitters and absorbers of infrared radiation
Good reflectors of infrared radiaiton
How do particles in a gas behave?
Move very quickly in random directions
They collide with each other and with the container walls
What happens when the temperature of a gas increases?
The gas particles move faster
The collisions become more intense
What happens when the temperature of a gas decreases?
The gas particles move more slowly
The particles move closer together
Collisions become less frequent
Gas condenses into a liquid
How can solid particles move?
They vibrate in a fixed and orderly position
How can liquid particles move?
They move around each other at random but they stay close together
What are the properties of a solid?
Why?
Fixed shape and cannot flow-Particles cannot move because they are in a fixed position
Cannot be compressed-There are no gaps between the particles because they are so close together
What are the properties of a liquid?
Why?
They flow and take the shape of the container-Particles can move around each other
Cannot be compressed- No gaps between particles because they are so close together
What are the properties of a gas?
They flow and completely fill the container- Particles can move quickly in all directions
They can be compressed- Particles are far apart and have space to move
What 4 ways is heat transferred?
Conduction
Convection
Evaporation
Condensation
What is conduction?
The transfer of energy by heating
How does conduction work in a metal?
The free electrons transfer heat energy to the cooler parts of the metal because they can collide with the ions as they move
What is convection?
The transfer of energy by heating through the movement of particles
What states of matter does convection occur in?
Liquids and gases
How does convection work?
-Particles nearest the energy source move faster, causing substance to expand and become less dense
-Hot particles rise vertically. As this happens the particles cool which causes them to become denser and sink
-Colder, denser particles sink, closer to the heat source again
What is evaporation?
Transfer of energy at the surface of a liquid
When a liquid becomes a gas
How does evaporation work?
-Particles that are moving most rapidly are located at the surface, they behave like a gas and escape
-This causes the energy of the liquid to reduce which results in a fall in temperature
What is condensation?
When a gas becomes a liquid
How does condensation work?
When a gas looses energy and cools, the particles become closer together and bonds form between them which releases energy
When does the rate of condensation increase?
When the temperature of the gas decreases
When does the rate of evaporation increase?
When the temperature of the liquid increases
What 2 factors affect the rate of evaporation and condensation?
The surface area of the liquid
If air is moving over the surface of the liquid
What 4 factors affect the rate at which materials transfer energy?
Surface area and volume of the material
Type of material
Nature of surface with which the material is in contact with
Temperature of the material
What is a U-value?
The measurement of the amount of energy lost from a building
If the U-value is low, what does this indicate?
The material is a good insulator
What is specific heat capacity?
The amount of energy required to change the temperature of 1kg of material by 1'C
What does the efficiency of a device refer to?
The proportion of energy that is usefully transferred
What does the amount of energy transferred by an electrical appliance depend on?
How long the appliance is switched on for
How fast the appliance transfers energy- Power
What does power measure?
The rate of energy transfer
What are the 3 types of energy sources?
Fossil fuels
Nuclear fuels
Biofuels
What are the 4 types of non-renewable energy sources?
Nuclear
Coal
Oil
Gas
What are the 6 types of renewable energy sources?
Wind turbines
Tidal/Wave
Hydroelectric power
Solar cells
Biofuels
Geothermal
What are the advantages of nuclear power?
Cost of fuel is low
Rate of fuel use if low
Doesn't produce carbon and sulphur dioxide emissions
What are the disadvantages of nuclear power?
Radioactive waste produced
Difficulty storing radioactive material
New nuclear power stations are costly
Decommissioning is costly
Radioactive contamination risks are high-Dangerous
What are the advantages of using coal as a power source?
Relatively cheap
Fairly easy to extract
What are the disadvantages of using coal as a power source?
Burning coal produces carbon and sulphur dioxide emissions which leads to global warming and acid rain
Not much coal left to rely on
What are the advantages of using oil as a power source?
Relatively easy to find
Large amounts of reserve stocks available
What are the disadvantages of using oil as a power source?
Produces carbon and sulphur dioxide emissions
Risks of pollution due to spillage
Destruction of animal habitats
What are the advantages of using gas as a power source?
Relatively easy to find
Large amounts of reserve stocks available
Doesn't produce sulphur dioxide emissions
What are the disadvantages of using gas as a power source?
Produces carbon dioxide emissions although less that coal and oil
Expensive pipelines and networks required
Visual pollution of landscape
Destruction of animal habitats
What are some examples of biofuels?
Liquid ethanol
Methane gas
Straw, nutshells and woodchips
What are the advantages of using wind turbines for electricity?
No fuel
Little maintenance
No polluting gases produced
Can be built offshore
What are the disadvantages of using wind turbines?
Visual and noise pollution
High initial capital building costs
Not very flexible in meeting demands
Variation in wind affects output-Unreliable
What are the advantages of using tidal and wave power?
No fuel required
No polluting gases produced
Barrage water can be released when demand is high
What are the disadvantages of using tidal and wave power?
Visual pollution
Hazard to shipping
Can destroy animal habitats
Variations in tide affect output-Unreliable
Very high capital costs to build them
What are the advantages of hydroelectric power?
Fast start0up time
No polluting gases produced
Water can be pumped back to reservoir when demand is low
What are the disadvantages of using hydroelectric power?
Involves damming upland valleys-Destruction of habitat
Need an adequate amount of rainfall
Very high initial costs
What are the advantages of solar panels?
Useful in remote locations
No polluting gases emitted
Small-scale production possible
What are the disadvantages of using solar panels?
Depends on light intensity-Unreliable
Use of high cost materials
Efficiency is poor
Visual pollution
What are the advantages of biofuels?
Flexible product
Cost effective
Little impact on environment
What are the disadvantages of biofuels?
Some pre-processing of material is required-Added cost
Limited resources due to land area requirements
What are the advantages of geothermal power?
No pollutants produced
Uses naturally occurring hot water and steam
Low start-up costs
What are the disadvantages of geothermal power?
Restricted to volcanic areas
Subsidence risk
What are renewable energy sources caused by?
Why?
The Sun:
-Causes evaporation which results in rain and flowing water
-Causes convection currents which results in winds a creation of waves

The Moon:
-Causes gravitational pull which creates tides
What is carbon capture?
How is this being done?
Why is this vital?
The capture and storage of carbon dioxide when its released through industry

Storing carbon dioxide in natural containers (old oil and gas fields) under the North Sea

Reduces the effects of global warming because less greenhouse gases are being released into the atmosphere
What is the purpose of transformers?
Change the potential difference of the alternating current supply before and after it is transmitted through the National Grid
What is the National Grid?
A network of cables, transformers and power stations
What does increasing the potential difference result in?
Reduces the current required for a given power. This reduction in current reduces energy losses in the cables when electricity is transferred to consumers
What is the purpose of step-up transformers?
Increase potential difference to 400,000 volts which allows power lines to transmit electricity from the power stations with reduced energy loss
What is the purpose of step-down transformers?
Decrease the potential difference to 230 volts and increase the current before its used by consumers so its relatively safe to use in homes
What is process of electricity reaching our homes?
Power station (25,000V)
Step up transformer
Power lines (400,000V)
Step down transformer
Houses/Shops (230V)
What is a transverse wave?
Where the oscillations are perpendicular to the direction of energy transfer
What are some examples of transverse waves?
Water waves
Electromagnetic waves
What is a longitudinal wave?
Where the oscillations are parallel to the direction of energy transfer
Show areas of compression and rarefaction
Name an example of a longitudinal wave
Sound wave
What form of wave is a mechanical wave?
It can be longitudinal or transverse
What do all waves transfer?
Energy
What are some examples of mechanical waves?
Water waves
Shock waves
Name all parts of the electromagnetic spectrum
Radio waves
Microwaves
Infrared
Visible light
Ultraviolet
X-rays
Gamma rays
What is different about opposite sides of the electromagnetic spectrum?
Radio waves have a low frequency and a long wavelength
Gamma rays have a high frequency and a short wavelength
What is the wavelength of a gamma ray?
10 to the power of -15 metres
What is the wavelength of a radio wave?
10 to the power of 4 metres
How many colours are present in visible light?
7 primary bands of colours which go from red to violet
What is the wavelength?
The distance between two successive peaks or troughs in a wave
What is the amplitude of a wave?
The peak movement of the wave from its rest point
What is the frequency of a wave?
What is frequency measured in?
The number of waves that pass in one second

Hertz (Hz)
What happens when a wave meets a surface?
The wave is reflected and refracted
What are radio waves used for?
Television and radio signals allow communication
What are microwaves used for?
Mobile phone networks (potential risk because it could lead to brain tumours)
Cooking-Water molecules absorb microwaves and heat up
What is infrared radiation used for?
Remote controls for televisions
Grills, toasters and radiant heaters
Optical fibre communication
What is visible light used for?
Morse code with torches
Photography
Fibre optics
What do sound waves cause?
Vibrations within a material/medium because of the longitudinal waves
What can sound waves not travel through?
A vacuum
What frequencies can humans hear?
20Hz-20,000Hz
How is pitch determined?
The frequency, as the frequency increases the pitch becomes higher
What are echoes an example of?
Sound being reflected at a surface
What happens to sound waves as an object moves towards you?
The wavelength decreases and the frequency increases, causing the pitch to rise
What happens to sound waves as an object moves away from you?
The wavelength increases and the frequency decreases, causing the pitch to drop
When an object moves away from an observer, what is it's light affected by?
The Doppler Effect
Why are there black lines in the spectrum of light?
The Sun contains helium and these black lines show when helium has absorbed light
What are the black lines called on a light spectrum?
Absorption spectrum
How is the absorption spectrum different for a distant star compared to the Sun's?
The position of the lines have moved towards the red side of the spectrum
Why are the black lines to the red side of the spectrum for a distant star?
Because of the Doppler effect which means their wavelengths have increased and the frequency has decreased
If lots of black lines are to the red side of the spectrum, what does this mean for the star?
It means that the star is moving away from us and that the further away a galaxy, the faster it's moving away
What does red-shift support?
The expansion of the universe
It suggests that everything is moving away from everything else
What does CMBR stand for?
Cosmic Microwave Background Radiation
What is CMBR?
Microwaves that are coming from all directions in space
The remains of energy created by the Big Bang
What does CMBR support?
The Big Bang Theory
What is reflection?
When a wave strikes a reflective surface and changes direction
What are the characteristics of reflected image?
Upright
Virtual
Laterally inverted
Same size as object
What is the incident ray?
The light ray that is travelling towards the mirror
What is the reflected ray?
The ray that is travelling away from the mirror
What are waves?
Vibrations that transfer energy from place to place without matter being transferred
What 2 waves must travel through a medium?
Sound waves
Seismic waves
What are the 2 areas in a longitudinal wave?
Compression
Rarefaction