Flashcards
P2
Cards in this deck (26)
- 1P2 Electromagnetic waves don't transfer any matter. What do they transfer?Energy.
- 2P2 Put the electromagnetic spectrum in order (lowest frequency to highest).Radio waves, microwaves, infared, visible light, ultraviolet, x rays and gamma rays.
- 3P2 How is the frequency of EM radiation related to the energy carried by its photons?Each photon carries a tiny quantity of energy, but not all photons have the same amount of energy. The amount of energy carried by a photon depends on the frequency of the radiation.
- 4What does the intensity of a beam of EM radiation mean?How much energy arrives at each square metre of surface per second.
- 5Name three types of ionising radiation.Ultraviolet, X-rays and gamme rays.
- 6Why is ionisation dangerous if it occurs in your cells?If your cells are exposed to ionising radiation, the damage to DNA molecules can cuase mutations, and the cells might start diving over and over again without stopping - cancer.
Very high doses of radiation can kill your cells altogether.
UV radiation from the Sun can damage living cells in the skin - leading to sunburn or skin cancer. - 7How do radiographers protect themselves from X rays?The radiographer might put lead shields over parts of your body that aren't being investigated. The lead absorbs X-rays, protecting you from unnecessary exposure. Radiographers also wear lead aprons or stand behind concrete to protcect themselves.
- 8What sort of radiation is used in conventional cookers?Infared radiation
- 9Briefly explain how microwaves cook food.Microwaves make particles vibrate, heating them up. Some microwaves are strongly absorbed by water molecules and so can heat things containing water. This is handy, because there's water in all food substances.
- 10Name three greenhouse gases.Carbon dioxide, methane and water vapour.
- 11How is ozone made in the atmosphere?UV radiation spliys an ordinary oxygen molecules, O2, into two oxygen atoms. One of these oxygen atoms combines with another O2 molecules to form an ozone molecule, O3.
- 12How is carbon dioxide returned to the atmosphere in the carbon cycle?Respiration in plants, animals and decomposers. Also, combustion.
- 13What has been happening to levels of carbon dioxide in the atmosphere in the last 150 years?It's been increasing, which must be because its being released into the air faster than it is being removed.
- 14What two effects does chopping down and burning trees have on the atmospheric carbon dioxide level?Plants are the main things which remove carbon dioxide from the atmosphere due to photsynthesis.
Burning the trees is combustion which adds lots of carbon dioxide into the atmosphere. - 15What is global warming?Global warming is a type of climate change, and it also causes other types, e.g. changing weather patterns.
- 16What's causing global warming? How do we know this?The rise in CO2 by increasing the greenhouse effect. There is a link between concentration of CO2 and global temperature.
- 17Give two possible consequences of global warming.Flooding in low-lying places due to ice melting. Water that is currently 'trapped' on land as ice runs into the sea, causing sea level to rise even more.
Some regions will suffer more extreme weather. Hurricanes form over water that is warmer than 26 degrees si the more warm water, the more hurricanes. - 18Why are radio waves and microwaves good at transmitting information over long distances?They don't get absorbed by the Earth's atmosphere as much as most waves in the middle of the EM spectrum.
- 19Describe two uses of microwaves.For mobile phone communications. For satellite TV, the signal from a transmitter is transmitted into space where it's absorbed by the satellite dish orbiting. The satellite transmits the signal back to Earth in a different direction where it's recieved by a satellite dish on the ground.
- 20What advantages do digital signals have over analogue signals?If you recieve a 'noisy' digital signal, its pretty obvious what it's supposed to be. So it is easy to 'clean up' the signal - the noise doesn't get amplified. This means they are much higher quality. Also, digital signals are easy to process using computers.
- 21What is a photon?A photon is a tiny 'droplet' or 'packet' of energy.
- 22What is the difference between a radio wave photon and a gamma ray photon?Radio wave photons have the lowest frequency and the least energy, and a gamma ray photons have the highest frequency and highest energy.
- 23Which is more intense - red light from the Sun or violet light from the Sun?Violet
- 24What can ionising radiation do to an atom?When a photon hits an atom or molecule, it sometimes has enough energy to remove an electron and change the atom or molecule.
- 25Why can only ultraviolet, X-rays and gamma rays cause ionisation?It takes a lot of energy to remove an electron from an atom or molecule so only types of radiation with high enough photon energy can cause ionisation.
- 26What are some uses of X-rays?Radiographers in hospitals can take pictures of people to see if they have broken bones. It can also be used in airports to check the contents of passengers' bags.
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- Flashcards on P2, created by jvmima on 19/05/2015.
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