Ch - 7 Flashcards
What is the function of sun on earth?
- Heats up the atmosphere, creating wind and producing waves.
- Water evaporated by the sun falls as rain, filling up reservoirs.
- Plants grown using sunlight from fuels - biofuels and fossil fuels
What are the diff forms of energy other than sun?
- Geothermal - produced in Earth’s core
- Nuclear - Elements that make up Earth’s crust.
- Tidal - Gravitational attraction of the moon
How is the energy that falls from the sun transferred?
Radiation (Visible light & Infrared radiation)
Why does solar energy need large collecting devices?
Low energy density
What is one issue with collecting solar energy?
- Expensive
- Inefficient
How do solar cells generate electrical power?
- Transfer energy from sunlight electrically producing a current
- This generates electricity.
What are solar cells also called?
Photovoltaic cells
What are solar cells made of?
Semiconducting materials
What are the advantages of a solar cells?
- Renewable
- Reliable
- No greenhouse gasses or pollution.
-Remote places
what are the disadvantages of solar cells?
- Need to be large scale
- Expensive
- sunlight is not a reliable source
What is the function of solar panels?
- Solar panels transfer energy from sunlight to thermal store of solar panels.
- Used to heat water in the pipes.
What does the solar furnace consist of?
- Large curved mirrors that focus the sun’s rays on to a small area.
What is the solar furnace used for in the end?
- Boil water
- Generate steam to turn turbine
- Generate electricity
What are the advantages of using solar panels?
- Renewable
- reliable
- No Greenhouse gasses or pollution
- Cut cost
What are the disadvantages of using solar panels?
- Large scale to produce High temp.
- Heat water in High temp.
- Not reliable
What are the fossil fuels?
Formed from remains of dead plants and animals
What are the diff types of fossil fuels?
- Coal
- Natural gas
- Crude oil
Where does chemical energy stored in fossil fuels come from?
Sunlight
Where was the energy from the sun transferred to?
Chemical energy store of plants by photosynthesis
What are the advantages of fossil fuels?
- Transport of electricity heavily relies on fossils available
- reliable
What are the disadvantages of fossil fuels?
- Millions of yrs to form
- non-renewable
- decreasing
supply - Completely run
out
- Pollutes
-CO2 —> Greenhouse effect- sulphur dioxide –> acid rain
What are the uses of fossil fuels?
- Transport
- Generating electricity
- Heating
What are majority vehicles powered by?
Petroleum
Where does petroleum originate from?
Crude oil (fossil fuels)
what are growing no. of vehicles being powered by?
- Electricity
- Zero carbon emissions
- Combination of resources
What is used to produce energy on-deman for electricity?
Coal and oil
What are the steps to do electricity generation by fossils?
- Burning
- Burning produces thermal energy
- Boils water creating steam
- Steam turns a turbine
- Electromagnet generates electricity
- Steam condenses and process repeats
What are biofuels made from?
Plant matter
Where does this energy from biofuel come from?
Sunlight transferred to chemical store of plants
What can be used in place of fossil fuels?
Ethanol or methane. (Half density of fossil fuels)
What are the advantages of biofuels?
- carbon neutral
- renewable
- powered by biofuel
What are the disadvantages of biofuels?
-Time consuming
- land n resources used
- co2
what is fission?
Energy stored in the nucleus can be released When the nucleus is broken in 2
Define nuclear fission.
When a large nucleus is broken into two smaller nuclei where energy is released.
How do nuclear powers generate electricity?
Fission reactions to heat water, this turns turbines to generate electricity.
What are the advantages of nuclear fission?
- no pollution
- safe
- Reliably on a large scale
- available
What are the disadvantages of nuclear fission?
- Finite supply
- non renewable
- radioactive waste
How is electricity generated by wave & tide power?
Red and fall of waves turns the turbines and generates electricity
what are the advantages of tide and wave energy?
- no pollution
- reliable
- renewable
- small systems
what are the disadvantages of tide and wave energy?
- expensive
- damages habitat
- few suitable location
- large scale.
What type of energy is there when water is stored above ground level?
Gravitational Potential Energy
What is this energy converted to and when?
K.e. because water flows down
What is the function of the turbine?
Generate electricity.
What are the advantages of hydroelectric dams?
- reliable n available.
- generates large scale
What are the disadvantages of hydroelectric dams?
- destroys habitats, town n villages
- releases large amounts of greenhouse gasses.
How is geothermal energy producing heat?
- Radioactive elements deep in earth release energy as they decay
- Geothermal heats up rocks
How is water heated and comes back up in geothermal energy?
- Water is poured in shafts below
- Water is heated by the rocks and returned to shaft.
- Steam is used to turn turbines and generate electricity.
- This heats homes.
What are the advantages of Geothermal energy?
- Renewable
- Reliable
What are the disadvantages of Geothermal energy?
- Small-scale production
- greenhouse gases
- expensive to build.
How is sun’s energy produced?
Nuclear fusion
What is nuclear fusion?
Involves the collision and bonding of hydrogen and nuclei to form helium nuclei, releasing nuclear energy in the process.
What is one requirement of fusion?
Extremely High temp. , like centre of star.
