Flashcards
P2.3 - Nuclear
Flashcards do conjunto (74)
- 1what is an isotope?an element with different amount of neutrons
- 2what is the stability like of an isotope?unstable
- 3what kind of nuclei produces a radioactive element?an unstable one
- 4what happens when nuclei decay?they give out ionising radiation
- 5what are the three types of ionising radiation?beta, alpha, gamma
- 6what element does alpha radiation cause?helium
- 7what is the size and the speed of movement for an alpha particle?big, heavy and slow moving
- 8what material can block the route of a alpha particle?paper
- 9what does a beta particle cause?a neutron to turn into a proton
- 10what is a beta particle?an electron
- 11what is the size and speed of movement like for a beta particle?middle
- 12what is the charge of a beta particle?-1
- 13what material blocks a beta particle?aluminium
- 14what ionising strength does gamma have?weak
- 15what is gamma?an em wave
- 16what change does gamma radiation do to an element?none - no change to element or charge
- 17what blocks gamma radiation?thick lead
- 18what sort of ionising strength does an alpha particle have?strong
- 19what is the charge of an alpha particle?2+
- 20when is gamma often released?after beta or alpha the nucleus gets rid of extra energy
- 21what is the nuclear equation for alpha?mass -4 4 0
element -> new element + he + y
atomic -2 2 0 - 22what is the nuclear equation for beta?mass same 0
element -> new element + e
atomic +1 -1 - 23where is beta radiation used?*thickness control of paper (eg)
*medical tracers - 24where is alpha radiation used?*smoke alarms
- 25where is gamma radiation used?*medical tracers
*radiotherapy (killing cancer cells)
*sterilising food and medical equipment - 26what occupations run a high risk of being contaminated by radiation?*radiographers
*pilots
*miners
*nuclear power station workers - 27how can the risks of contamination of radiation be reduced?*wearing protective clothing
*avoiding the radiation as much as possible
*having regular health check ups - 28the damage of radiation contamination to health depends on what things?*dose
*type
*amount of exposure - 29what does high doses of radiation increase the risk of?cancer
- 30what is radiation measured in?sieverts or millisieverts (Sv or mSv)
- 31what is half life?the average time for the number of unstable nuclei in a radioactive isotope to halve
- 32can it be predicted when a nucleus will decay?no
- 33what causes a particle to be strongly ionising?the electrons are easily knocked out
- 34what is radioactivity measured in?bequerels (Bq)
- 35where does background radiation come from?naturally occurring unstable isotopes
- 36give examples of where background radiation can come from?the sun- cosmic rays, hospitals, industry, nuclear explosions
- 37why does radiation cause health problems?radiation causes ionisation which leads to cells mutating which divide rapidly and can cause cancer
- 38what form of radiation is more dangerous inside the body?alpha as it cannot get out so does a lot of damage to a small area
- 39what form of radiation does the most damage outside of the body?beta and gamma as they can easily get through skin and organs quickly
- 40what is nuclear fission?splitting up a large atomic nucleus
- 41what elements are often used in nuclear fission?uranium 235 and plutonium 239
- 42how does nuclear fission work in a nuclear power station?splitting up nucleus releases lots of heat energy, heat energy heats up water, produces steam which turns turbines to make the electricity
- 43describe the process of nuclear fission*neutron absorbed into nucleus of uranium
*causes uranium to split and that releases heat and 3 neutrons
*these then go on to split up more nuclei - 44what reaction happens in nuclear fission?a chain reaction
- 45how is the chain reaction controlled in nuclear fission?control rods absorb some of the extra neutrons released stopping them splitting up more nuclei and slows down the reactions
- 46why does the chain reaction in nuclear fission need to be controlled?to avoid overheating or explosion
- 47what is nuclear fusion?the joining of two small atomic nuclei
- 48what are the isotopes used in nuclear fusion?1 2
H and H
1 1 - 49what is the product of nuclear fusion?3
He
2 - 50why is fusion better than fission?*more energy released
*no radioactive waste left behind
*lots of hydrogen available - 51why is nuclear fusion not yet efficient enough?no material on earth can withstand the temperatures needed
(around 10 million degrees) - 52what happened in 1989 with the scientists that claimed they achieved cold fusion?they claimed they performed fusion at room temperatures but the results weren't reproducible
- 53what cant happen in nuclear fusion and how is this avoided?the hydrogen atoms cannot touch the sides
by using a magnet - 54how is low level nuclear waste disposed of?burying in secure landfill sites
- 55how is intermediate level waste disposed of?sealed in concrete blocks and put in steel canisters for storage
- 56how is high level radioactive waste disposed of?sealed in glass and steel, cooled for around 50 years and then moved into more permanent storage. it could then be buried but would have to be a place with no earthquakes
- 57why is a fusion bomb more efficient than a fission bomb?releases more energy
- 58what is the life cycle of a smaller star?*nebula
*protostar
*main sequence star
*red giant
*planetary nebula
*white dwarf
*black dwarf - 59what happens in the nebula/protostar?*initially dust and gas
*gravity makes gas and dust forming the protostar
*gravity converts to heat energy and causes fusion of hydrogen to form helium
*helium give out lots of heat and light and star is born - 60what happens in a main sequence star?*massive amounts of hydrogen so lots of fusion so lots of energy
*can maintain energy so can last millions or billions of years
*fusion pressure provides outwards force balancing out gravity
*long lasting stable period
*elements as heavy as iron made through fusion - 61what happens in a red giant?the star swells and turns red as it cools
*heavier elements made by fusion of helium
*hydrogen starts to run out - 62what happens in a planetary nebula?*becomes unstable
*ejects its outer layer of dust and gas - 63what happens in a white dwarf?*a hot, solid, dense core is left
- 64what happens in a black dwarf?a cool white dwarf that eventually disappears
- 65what is the life cycle of a big star?*nebula
*protostar
*main sequence star
*super red giant
*super nova
*neutron star
*black hole - 66what happens with a super red giant?*hydrogen starts to run out
*heavier elements made by fusion
*star swells turning red - 67what happens in a supernova?*more fusion to glow brightly again
*expand and contract several times
*form elements heavier than iron and ejects them to form new planets and stars
*explodes in a supernova - 68what is a neutron star?*exploding supernova throws outer layers of dust and gas into space
*leaves a dense core which is the neutron star - 69when is a black hole formed?if the star is big enough
- 70what is the 'plum pudding' model of the atom suggest?that atoms were spheres of positive charge with electrons stuck on them
- 71what did Rutherford, Marsden and Geiger's alpha particle scattering consist of?firing alpha particles at gold foil
- 72some of the alpha particles passed straight through the gold foil, what did this show?lots of space in an atom
- 73some alpha particles were deflected at small angles what does this show?nucleus has positive charge
- 74some alpha particles were deflected at very large angles what does this suggest about the nucleus?it has a large mass and a large positive charge
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- AS - Level Physics (P2) FlashCards sobre P2.3 - Nuclear, criado por Kelly Jowett em 29-04-2015.
- Criado por
- Kelly Jowett
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