P1 - Energy Flashcards
Define renewable energy
An energy source that is replaced faster than it can be used
Give examples of renewable energy sources.
Wind, waves, tides, hydroelectric, biofuel, geothermal, solar
How does the step-up transformer increase the efficiency of the National Grid?
It increases the voltage and decreases the current, therefore reducing energy loss along the cables.
Explain one effect burning fossil fuels has on the environment.
produces greenhouse gases, nitrogen oxides (trigger asthma attacks), sulphur dioxide (leads to acid rain)
Pumped storage hydroelectric power stations have a short start-up time. Why is this important?
to meet surges in demand/ start generating electricity in a short time
Give an advantage of a pumped storage hydroelectric power station.
can store energy for later use renewable
Using mainly wind turbines to supply electricity might cause fluctuations in the electricity supply. Why?
wind speeds fluctuate so turbines don’t generate electricity at a constant rate
Between 2002 and 2008 the amount of electricity used in the UK decreased. Suggest why.
energy efficient lighting used/ developed; increase in energy costs so people switch off more; ‘switch off’ campaign raises awareness of environment
Although gas boilers are very efficient, some energy is wasted. What happens to this waste energy?
it is transferred to the surroundings, becomes spread out; wasted as sound
Give a disadvantage of a large scale hydroelectric power station.
large areas of land flooded, homes and habitats destroyed
What is the National Grid?
system of cables and transformers
Why is transferring electricity directly to local homes more efficient than using the National Grid?
less energy is wasted as the cables used are shorter
A solar cell can be used to recharge a mobile phone. Suggest and explain one factor that would affect the charging time.
time of day, position of solar cell, angle of solar cell towards Sun, latitude, cloud cover, dust; all cause a change in light intensity
What are the advantages of using solar cells instead of fossil fuel power stations to generate electricity?
no air pollution, free resource, renewable, usable in remote areas, no need to connect to National Grid
Fitting a new hot water boiler costs £1800 but saves £200 per year. What is the payback time?
9 years
Explain why using an energy efficient light bulb rather than an ordinary light bulb reduces carbon dioxide emissions.
less electricity needs to be generated from power stations, less fossil fuel needs to be burnt
Give two advantages of burning wood instead of coal.
carbon neutral, renewable, conserves fossil fuel reserves
Why do wood burning stoves have a large surface area?
to increase the rate of energy transfer
Do you agree with the statement that ‘replacing old freezers with more energy efficient freezers’ benefits the environment?
y- less fossil fuels burnt as less electricity needed, so fewer greenhouse gases emittedn- old freezers must be dumped and there are hazardous chemicals inside them
How do you reduce energy loss from the loft/roof?
Fibreglass
How do you reduce energy loss from the walls?
Cavity wall insulation such as polystyrene beads
How do you reduce energy loss from windows?
double/ triple glazing
How do you reduce energy loss from doors?
draught excluders
why are electricity companies selling electricity at night at a lower rate?
Supply exceeds demand
Leaving a 1kW radiator switched on for the same length of time as a 40W lamp is worse for the environment. Why?
radiator uses more energy,more electricity is needed,more fossil fuel is burnt, moreCO2 produced
What is meant by the word efficient?
most input energy isusefully transformed
Give examples ofstored energy.
gravitational, elastic,chemical
Why must the totalenergy input equal the totalenergy output?
energy cannot be createdor destroyed
Name the useful andwasted energy output from ahair dryer.
useful thermal and kineticand wasted sound energy
Name the useful andwasted energy output from aTV.
useful sound and light,wasted thermal
what does it mean todecommission a nuclearpower station?
remove radioactive waste/fuel- very expensive process
How could companiesreduce CO2 emissions?
use more nuclear power,use more renewable energysources, use carbon capturetechnology
Give the advantages ofusing nuclear power.
little fuel needed for a largeamount of energy released(concentrated source of energy),continuous process, nogreenhouse gas emissions
give advantages anddisadvantages of tidal powergenerating systems.
renewable, calms coastalwaters, low running costs, noair pollution but highinstallation costs, timedependent, disturbs coastalhabitats
Give advantages anddisadvantages of wind power.
renewable, no air pollution,leave land undamaged whenremoved but unsightly andnoisy, require large areas ofland as many turbines areneeded
How does a vacuumflask keep the liquid insidehot?
plastic cap is poor conductor & stopsevaporation of hot liquid as particlescannot escape; stops convectioncurrents so no heat loss by convection;vacuum prevents heat loss byconduction & convection as both requireparticles; silver lining to reflect IR backinside the flask and reduce heat loss byradiation
Why do arctic foxes havesmall ears?
ears have a small surfacearea so reduce heat loss
Why is foam a goodinsulator?
air cannot circulate insidefoam as the air bubbles aretrapped inside the foam
What is meant by theterm U-value?
how effective an insulator amaterial is; the lower the Uvalue,the better the material isat insulating
What is geothermalenergy?
energy from hot rocks inthe Earth
Why does theNational Grid include step-uptransformers?
to increase the voltageacross the cables and reduceenergy loss
Why are copper pipesinside a solar panel paintedblack?
black is a goodabsorber of radiation sothere will be a fastertransfer of energy to thewater
Why is electricityessential for moderncommunication and publichealth?
Many devices transform onetype of energy into others;doctors and hospitals can storevaccines and blood inrefrigerators; internet runs onelectricity
What is the role ofthe step-down transformer?
It reduces the voltage to asafe working value for homesand offices
