END OF YEAR 9 part 1 Flashcards
What is thermal radiation and what can it travel through
It is electromagnetic radiation and it can travel through a vacuum
What do you all objects emit and what happens if the object is hotter
Infrared radiation and the hotter an object is the more infrared it emits
What are light and shiny surfaces best at
Reflecting thermal radiation
What are dark Matt services best at
Emitting and absorbing thermal radiation
What does the kinetic theory state
All matter is made up of small particles which are constantly moving
How are particles in a solid held together and what are the forces like
In fixed positions and the forces are strong
What are particles like in a liquid and what are the forces between them like
The particles move about at random and are in constant with each other and the forces between them are weaker than in solids
What are particles in a gas like and what are its forces like
The particles move about randomly and are further apart than particles in a liquid or solid. the forces between the particles are negligible
Why are metals the best conductors of heat
Because they have free electrons which defuses, spread out, and collide with other free electrons and ions. in this way they transfer kinetic energy
Why are materials like wool and fibreglass good insulators and why are they poor conductors
They are good insulator is because they contain air trapped between the fibres and they are poor conductors because they have no free electrons
What is convection, what is it caused by and how is it created
Convection is the circulation of the fluid. it is caused by heating it and it is created when hot less dense fluid rises and cold less dense fluid sinks
What is evaporation and how can it be increased
Evaporation is when a liquid is turned into a gas and can be increased by increasing the surface area of a liquid, increasing the temperature or by creating a drought of air.
Cooling by evaporation of a liquid is due to what
To the fast moving molecules escaping from the liquid. this means that the average kinetic energy of the remaining particles is reduced which lowers temperature of the liquid
What is condensation and how can it be increased
It is when a gas is turned into a liquid and can be increased by increasing the area of the surface or reducing the temperature of the surface
What does the rate of energy transfer to or from an object depend on
The shape, the size,the type of material of the objects, the materials the object is in contact with and the temperature difference between the object and its surroundings
The greater the mass of an object……………….
The more slowly its temperature increases when it is heated
What does the energy needed to change the temperature of a substance depend on and what is the equation
It depends on its mass, it’s the civic he capacity and the change in temperature. The equation is MCO
MassX specific heat capacity X temperature change
What is the specific heat capacity
It is the energy needed to raise the temperature of 1 kg of a substance by 1°C
What do you solar panels use
Solar radiation to heat water but are expensive to buy
What are the forms of energy
Chemical energy, Kinetic energy, gravitational potential energy, elastic potential energy, electrical energy, light energy, sound Energy, and nuclear energy
Energy can’t be created for destroyed. Give an example
When an object falls, its gravitational potential energy decreases and its kinetic energy increases. this is the conservation of energy
What is useful and wasted energy
Useful energy is energy in the form we need it and wasted energy is not useful energy
What is the Sankey diagram used for
To represent the energy transfers in a device
What do you both useful and wasted energy end up being
Transferred to the surroundings which become warmer
What is energy measured in
Joules
What are the two ways that you can calculate efficiency
- efficiency equals useful energy transferred divided by total energy supplied times 100
- Efficiency equals useful power output divided by total power input times 100
What is the maximum efficiency of a machine
100%
How can efficiency be improved
By reducing friction and reducing electrical resistance
What is power and what is it measured in
It is the rate of transfer of energy and it is measured in watts
What does 1KW equal
1000 W
What is the kilowatt hour
It is the energy supplied to a 1KW device for one hour
What is E = p X t
Energy kWh equals power kW times time hours
How do you find the total cost
Number of KWh used X cost per KWh
What does the cost effectiveness of an appliance depend on
The amount of money needed to buy it, it’s running costs and any environmental costs
What are electricity generators in power stations driven bye
Turbines
What are the three fossil fuels
Coal, oil and gas
What are the advantages and disadvantages of fossil fuel power stations
The advantages are that it’s reliable and not dependent on weather. the disadvantages are that it produces greenhouse gasses and sulphur dioxide
What could be used to stop carbon dioxide emissions onto the atmosphere
Carbon capture and storage
What are the advantages and disadvantages of nuclear power
The advantages are there are no greenhouse gasses and more energy is released per kilogram than from fossil fuels. the disadvantages are that radioactive waste is produced and it stays dangerous for hundreds of years
What power stations provide a constant amount of electricity
Nuclear, coal and fuel power stations
What is the start-up time
It is the time needed before new powerstation can start producing electricity.natural gas power stations have the shortest start-up times, nuclear have the longest
What does it mean to discommission a nuclear power station
It means to dismantle and remove radioactive waste and Fuel
What are renewable sources of energy
Biofuels such as methane and ethanol
How many times can renewable energy be used
Again and again
What is a wind turbine
It is electricity generator on top of a tall tower
How do you waves generate electricity
By turning a floating generator
What are hydroelectric generators turned bye
Water running down the hill
Why does a tidal power trap water at each high tide
To use it to turn generators
What are solar cells
They are flat solid cells that convert solar energy is directly into electricity
What do solar heating panels use to heat water directly
The suns energy
What are the advantages and disadvantages of renewable energy sources
The advantages are that they will never run out, they don’t produce greenhouse gases and many can be used in remote areas. the disadvantages are that they can affect plant and animal life, they are often weather dependent and they do not always produce as much electricity as fossil fuel power stations
What is the National Grid
It is a network of cables and Transformers that distributes electricity to our homes from power stations
Why are underground cables a bad idea
They would be more expensive , would be much more difficult to repair and to bury where they can cross canels rivers and roads
How do you find the frequency
Velocity/wavelength
How do you find the energy needed to change state
Mass X specific latent heat
E=mL
How do you find the energy
Mass X specific heat capacity X temperature change
E=mcø
How do you find the mass
Density X volume
How do you find the useful energy
Efficiency X total energy
How do you find the distance
Speed X time
How do you find the energy supplied
Power X time
