Topic 4 - Energy Resources and Energy Transfers Flashcards
What are the 8 energy stores?
Kinetic
Gravitational
Chemical
Elastic
Thermal
Magnetic
Electrostatic
Nuclear
What are the 4 energy transfers?
Mechanically (Through forces)
Electrically
By heating
By radiation (light and sound)
What is the principle of the conservation of energy?
energy can’t be created or destroyed, only transferred between different stores.
The equation is efficiency = (useful energy output / total energy output) x 100, but what are the units and rearrangements?
Efficiency = (useful energy / total energy) x 100
Useful energy = (Efficiency x Total energy) / 100
Total Energy = (Useful energy x 100) / efficiency
Efficiency = (%)
Useful energy = (Joules, J)
Total energy = (Joules, J)
How is a Sankey diagram drawn?
The equation is work done = force x distance moved
w = f x d, but what are the units and rearrangements?
w = f x d
f = w / d
d = w / f
w = Work done (Joules, J)
f = Force (Newtons, N)
d = Distance moved (Metre, m)
What is the relationship between work done and energy transferred?
Work done = Energy transferred
The equation is GPE = m x g x h, but what are the units and rearrangements?
GPE = m x g x h
m = GPE / (g x h)
g = GPE / (m x h)
h = GPE / (g x m)
GPE = Gravitational Potential Energy (Joules, J)
m = Mass (Kilograms, kg)
g = Gravitational field strength (N/kg)
h = height (Metres, m)
The equation is KE = 1/2 x m x v², but what are the units and rearrangements?
KE = 1/2 x m x v²
m = 2 KE / v²
v = √2KE / m - ALL ROOTED
KE = Kinetic Energy (Joules, J)
m = Mass (kilograms, kg)
v = Velocity (m/s)
What is the link between GPE and KE?
Because energy is not created or destroyed, if an object falls, all its energy will be transferred to KE (Provided there is no air resistance etc). Therefore, loss of KE = Gain in GPE, and GPE + KE = Work done
What is power?
The rate of transfer of energy / the rate of doing work.
The equation is p = w / t OR p = e / t, but what are the units and rearrangements?
p = w or e / t
w or e = p x t
t = w or e / p
w = work done (Joules, J)
e = energy transferred (Joules, J)
p = power (Watts, W)
t = time (Seconds, s)
What are the energy transfers involved in generating electricity using wind?
KE from the wind turns blades, connected to a turbine. The turbine spins, connected to a generator, which takes kinetic energy and transfers it into electrical energy.
What are the energy transfers involved in generating electricity using water?
KE of the water spins a turbine, connected to a generator that transfers the kinetic energy into electrical energy.
What are the energy transfers involved in generating electricity using geothermal resources?
Thermal energy from the ground used to heat water, which turns to stream, and is pressed through narrow pipes. The thermal energy has been converted to kinetic energy, used to spin a turbine, which spins a generator, which turns this kinetic energy into electrical energy.
What are the energy transfers involved in generating electricity using solar heating systems?
Light energy from the sun is used to heat water so is transferred into thermal energy.
What are the energy transfers involved in generating electricity using solar cells?
Light energy from the sun is transferred by the solar cells into electrical energy.
What are the energy transfers involved in generating electricity using fossil fuels?
Chemical energy in the fossil fuel (i.e. coal) is transferred to heat energy as it causes the water to evaporate as it is heated. Steam travels through narrow tubes - the heat energy was transferred to kinetic energy, which makes the turbine spin, which is connected to a generator, and its KE transferred to electrical energy.
What are the energy transfers involved in generating electricity using nuclear power?
Nuclear energy transferred to heat energy as it is used to heat up the water. This heat is then transferred to KE, which spins a turbine connected to a generator that transfers the KE from the turbine into electrical energy.
What are the advantages and disadvantages of methods of large scale electricity production from various renewable and non-renewable resources?
Renewable energy (wind, water, geothermal, solar): All have a potentially infinite energy supply, but are usually more costly, and less reliable.
Non-Renewable energy:
-Fossil fuels: Cheaper than most renewable sources, but harmful for the environment because they release greenhouse gases which cause global warming.
-Nuclear power: A small amount of radioactive material produces a lot of energy, but they produce highly toxic nuclear waste which needs to be safely stored underground for many years.
