P2a: Collecting energy from the Sun Flashcards
Describe some advantages of using photocells to provide electricity(5)
no moving parts - low maintenance + long life
no need for power cables - can be used in remote locations
no need for fuel
renewable energy resource
no polluting waste
Describe some disadvantages of using photocells to provide electricity(3)
very large area of photocells needed to gen enough electricity for small town
no power at night in bad weather
difficult and expensive to store energy produced by photocells
How does light produce electricity in a photocell? (3)
light energy absorbed by silicon atoms in the photocell
electrons are knocked loose from the silicon atoms in the crystal
electrons flow freely in a circuit, creating DC
What does the current and power produced in a photocell depend on? (3)
+light intensity, +electricity
+surface area exposed, +electricity
-distance from light source, +light intensity, +electricity
Describe some advantages of using wind turbines to provide electricity(3)
renewable energy resource
no polluting waste
quite cheap to run as it is tough and reliable
Describe some disadvantages of using wind turbines to provide electricity(4)
visual and noise pollution
dependent on wind speed - impossible to increase supply when there’s extra demand
appropriate space and position needed - need to be spaced out and built in windy places
expensive to set up wind farm, especially out at sea
How do wind turbines harness energy from the Sun? (2)
winds are convection currents set up in the atmosphere by energy from the Sun
the KE of the wind can turn the blades, driving wind turbine, which turns a generator, producing electricity
How does passive solar heating work? (4)
light energy from sun passes through glass as it is transparent to Sun’s radiation
light energy absorbed by surfaces which heats them up
heated surfaces emit longer wavelength infrared radiation
longer wavelength radiation reflected by glass back into the building
What must an efficient solar collector be able to do
track the position of the Sun in the sky to make sure it is always facing the Sun and collecting solar energy
