Flashcards in P3 Deck (18):
What is the greenhouse effect?
-some radiation frequencies pass through the ozone layer
-heat up earth earth absorbs radiation
-emits it in evening
-radiation blocked from leaving earth by greenhouse gases(methane,water vapour,carbon dioxide)
Warms earth up more
What is carbon dioxide?
Over last 200 years co2 increase correlates with temperature increase
What is the effect of global warming?
temperature causes glaciers to melt
-sea levels rise
-extreme weather due to evaporating water
-increased convection in the atmosphere, greater wind speeds
What is the power formulae
Energy transferred(joules)= power(watts)•time(seconds)
Energy transferred(KWh)= power(KW)•time(hours)
Appliance current(A)= Appliance power(w) divided by supply voltage (v)
What is current in a circuit?
-a component that transfers electrical energy into useful forms
-current in connecting wires wastefully transfers electrical energy to heat
What is the formula for cost of electricity?
Cost of electricity=units•cost per unit
What is a sankey diagram?
thickness of arrow=amount of energy
What is the formula for energy efficiency?
Efficiency=energy usefully transferred divided by total energy transferred
How can we save electricity?
Use A rated appliances
Turning off components
Use transport effiency
Better insulation in houses
More efficient power stations
How do generators work?
A magnet turns inside a role of copper, wire the magnetic field changes as the magnet rotates
Why is the voltage higher when being transported?
More efficient, as less electricity is wasted, because the current is lower
What are the advantages and disadvantages of nuclear power?
Produces large amounts of electricity
Cheaper than coal and gas
No greenhouse gases
Efficient needs little fuel
Stations are expensive to decommission
What are the advantages and disadvantages solar energy?
Cheap when running
Relies on sun
What are the advantages and disadvantages wind?
Can be built on land and see
Large amount of land needed
Expensive to set up
Produces low frequency noise
What are the advantages and disadvantages of fossil fuels?
Cheaper than renewables
Have to rely on other countries
What are the advantages and disadvantages biofuel?
Medium power output
Needs large amounts of land to be produced
Expensive to produce
Trees grow slowly
What are the advantages and disadvantages hydroelectric
Can provide large amounts of electricity
Can be turned on and off quickly
Can pump water back behind the dam to store energy
Can flood areas
Rotting plants in the water produce methane gas
Cost a lot to build