Energy Flashcards
What are the nine types of energy?
Gravitational Potential Chemical Sound Elastic Kinetic Heat Light Electric Nuclear
What is the law of conservation of energy?
Energy cannot be created or destroyed, only transferred from one type to another
What will all energy eventually be transferred to?
Hear energy
Where does all energy come from?
The sun
What do Sankey diagrams show?
All energy transfers taking place in a process {to scale
Where does the total of the input energy go on a Sankey diagram?
The line on the far left of the diagram, width of initial arrow
Where do useful energies go on Sankey diagrams?
Out to the right, continuing straight from the width of the initial arrow
Where does waste energy go in a Sankey diagram?
Down
What is the equation for efficiency?
Efficiency - useful energy out / useful energy in x 100%
How do you turn a fraction into a number then the number into a percentage?
Take the fraction and divide the top by bottom then times it by 100
When an energy is transferred through a wire, what always happens to some of the energy?
Some energy is always lost
When energy is lost through a wire, why is it lost and what is it lost as?
It is lost due to the current and material, it is lost as heat energy
What is current?
Current is the flow of electrons through a wire or component
What is resistance in electrons?
When electrons move through a wire and they collide with other atoms
What happens every time electrons collide?
Energy is transferee to the electrons as heat
What is voltage?
Voltage is energy per electron
What is the equation for power?
Power = current x voltage
What must you do to raise current?
Lower voltage
What must you do to raise voltage?
Lower current
If you halve the voltage what must you do to the current?
Double the current
What do we use to convert between current and voltage?
A transformer
What does a step up transformer do?
It increases voltage and decreases current
What does a step down transformer do?
It decreases voltage and and increases current
What do transformers do in the national grid?
Stop the wires on pylons breaking
What are the three ways of heat transfer?
Infrared radiation
Convection
Conduction
What can infared radiation go through?
Everything
What can convection go through?
Liquids and gases
What can conduction go through?
Solids
What emits infared radiation?
Everything with a temperature above absolute zero
What is convection?
Convection is the transfer of hear through a fluid (liquid or gas) caused by molecular motion
What is conduction?
Conduction is the transfer of heat or electric current from one substance to another by direct contact
What is infared radiation?
Infared radiation is energy that is radiated or transmitted in the form of Ray’s or waved or particles
What are three things we want heat transfer for?
Cooking
Heating
Sun warming the earth
What are three things we do not want heat transfer for?
Heat loss form our homes
In cars
On machines
Why is unwanted heat transfer bad?
Unwanted heat transfer is bad because it uses up more energy, it costs us money and it damages the world
What are two methods to prevent heat loss?
Lubrication and thermal insulation
How does thermal insulation prevent heat loss?
If you use a material with a low thermal conductivity {doesn’t transfer heat very well} ur will insulate hot locations, keeping them hot. This is used in buildings
How does lubrication prevent heat loss?
Reduces frictions which not only reduces heat loss but also reduces wear and tear on moving parts. This is used for machines
What three types of energy cannot be stored?
Sound energy cannot be stored, light energy cannot be stored, electrical energy cannot be stored.
What six types of energy can be stored
Kinetic energy, heat energy, elastic potential energy. Nuclear energy, chemical energy and gravitational energy can be stored.
What is the equation for working out gravitational potential energy?
Gravitational potential energy = mass x gravitational field strength
What unit is gravitational potential energy measured in?
Joules
What unit is mass measured in?
Kg
What unit is gravitational field strength measured in?
N/Kg
What is gravitational field strengt also known as?
Acceleration
What is gravitational field strength a measure of?
A measurement of how much a planets gravity pulls on an object
What is the earths gravitational field strength?
10N/Kg
What is thermal conductivity?
Thermal conductivity is the rare at which heat transfers through a specific material
The higher the number of the thermal conductivity… {what does it mean?}
… the more heat lost
What is rare of cooling?
How quickly heat is lost
What did kinetic energy depend on/
Mass and velocity
What is the equation for kinetic energy?
Kinetic energy = 1/2 x mass x velocity^2
What is the unit for velocity ^2
M/s
What does gravitational potential rely on?
Gravity, mass and vertical height
What does kinetic energy and gravitational potential have in common?
Mass
Maximum GPE = ?
Maximum GPE = Maximum KE
Maximum KE = ?
Maximum KE = Maximum GPE
When is GPE at max and when is it at minimum?
At max at its highest point, at min at lowest point {ground
When is KE at max and when is it at minimum?
At max at its lowest point {ground} at min at highest point
How do you times by 100%?
Times by a hundred and add a % sign to the end
What are the seven types of renewable energy?
Solar Wind Wave Hydroelectric Geothermal Biomass Tidal
What are the four types of non renewable energy?
Oil
Coal
Gas
Nuclear
What is non renewable energy?
A non renewable source of energy cannot be sustained and will run out
What are the nine energy sources?
Hydroelectric Geothermal Fossil fuels Wave Solar Wind Biomass Nuclear Tidal
What’s the mnemonic for remembering the 9 energy sources?
Hermoine Gets Food When She Wants But Not Today
What are the two methods of turning a turbine?
Heat and direct
What are the three steps in the heat method of turning a turbine?
1) Heat is generated
2) Heat turns water to steam
3) Steam turns a turbine
What happens in the direct method of turning a turbine?
The source (water or wind) directly pushes the turbine
What does solar power do instead of moving a turbine to produce electricity?
The sunlight makes electrons move
Which four energy sources use the direct method of producing energy?
Tidal
Hydroelectric
Wave
Wind
Which four energy sources use the heat method of producing energy?
Fossil fuels
Nuclear
Geothermal
Biomass
What are three advantages of renewable energy?
Won’t run out
No greenhouse gases produced
Free fuel
Cheap to run
What are three disadvantages of renewable energy?
Infrastructure is expensive
Generally unreliable
Can damage the environment
Don’t release as much energy as fossil fuels
When an item is descending, what happens to the gravitational potential energy?
Gravitational potential energy will be lost
