P2 Living For The Future Flashcards
Revise how photocells work in revision guide
Pg. 13
How does passive solar heating work
Sunlight comes through the window and its radiation is absorbed by the objects inside, this then slowly releases em heat over time and glass reflects radiation back inside the building
What are the advantages And disadvantages of wind turbines
Renewable source of energy and doesn’t pollute, however doesn’t work without wind, can be noisy and spoils views
Why does the national grid step up the voltage to 400,000V when transporting electricity
Leads to: reduced energy loss, reduced distribution costs, cheaper electricity for customers.
Why does the transformer increase the voltage and lower the current
Because a higher current means that the wire gets hotter so there is an increase in resistance
What is ionisation
The loss or gain of electrons
What are the properties of alpha radiation
Causes the most ionisation, has a short range and is easily absorbed by a sheet of card
What are the properties of beta radiation
Has a range of about 1 m, is absorbed by a few millimetres of aluminium
What are the properties of gamma radiation
More penetrating, a few cm of lead stops it, but some can also pass through several metres of lead or concrete
What must be taken into account when identifying the type of radiation
Background radiation
What are the uses of radioactivity
Smoke alarms, thickness in a paper rolling mill, sterilising medical equipment, tracking of blood and to detect blockages in pipes
How do we deal with nuclear waste
Low level radioactive waste can be buried in landfill sites, high level is encased in glass deep underground or reprocessed
What are the dangers of radioactive waste
Remains radioactive for thousands of years, stored where it can’t leak into water supplies, terrorists could get it and contaminate water supplies
Advantages and disadvantages of nuclear power
Fossil fuel not used, greenhouse gases aren’t released, but t very high maintenance and decommissioning costs, risk of accidents
What are the properties of a black hole
Cannot see a black hole as light can’t escape form it, such is the size of its gravitational force, where large stars used to be, large mass small size
How does centripetal force work on moons with planets with stars
Acts towards the centre of the circular orbit, gravitational attraction is the source of the centripetal force
What needs to be specialised about a space suit
Dark visor stopping astronauts being blinded, pressurised suit with oxygen in it, can survive up to 120degrees, but also -160 degrees
Advantages and disadvantages of unmanned spacecraft
Costs less, doesn’t out astronauts lives at risk, but have to be reliable as they can’t be fixed up in space alone
What’s the difference between asteroids and planets
Asteroids have a low mass, and a planets gravitational force prevents it joining together with another planet
What are some beliefs as to how moon was formed and what evidence is there to back this up
2 planets collided, the iron core of the other planet joined with our core core, then the less dense rocks began to orbit and they joined to form our moon. The evidence is that the moon has a lower density than earth, there is no iron on the moon, the moon has the exact same oxygen composition as earth
What would happen if a NEO collided with earth
It would end life on Earth, to avoid this we could send a rocket up, altering its course to hopefully miss earth
What is red shift
When a source of light is moving away form an observer, it’s wavelength appears to increase which shifts light towards the red end of the spectrum. When scientists look at the sun there is a pattern of lines across the spectrum, however when they look at
Isn’t from different stars the pattern is the same however it is closer to the red end of the spectrum, suggesting that it is older
How are stars formed
Nebula clouds are pulled together by gravity, over millions of years the core becomes hot enough for nuclear fusion to take place. Hydrogen joins together to form hellium nuclei and energy is released, the star will shine until this burns out
Revise the end of a stars life
Pg. 20
What are the advantages of photocells
Don’t need much maintenance, don’t need fuel, don’t cause pollution, a renewable energy, however doesn’t produce energy when it is dark
