Atoms, Radiation and Stars

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  • Created by: Eloise
  • Created on: 02-05-16 16:46
Explain the plum pudding theory and how Rutherford disproved it
PP: sphere of positive charge with tiny electrons stuck in it. RD: fired alpha particles at thin gold foil, most went straight through the empty space some deflected completely whilst others deflected slightly
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What is radioactivity?
Random process, unaffected by physical conditions, where the nuclei of atoms decay into other elements and give out radiation
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Name the three sources of background radiation
1) Naturally occurring unstable isotopes 2) From space, cosmic rays 3) man made sources (nuclear accidents, waste and weapons)
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State the 3 types of radiation and their properties
Alpha: helium nucleus (2 protons and neutrons), heavy/big, slow moving, do't penetrate, strongly ionising. Beta: electrons, negative charge, small and fast, converts neutrons to protons. Gamma: Penetrate, weak, no mass, no charge, EM waves
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What is the definition of half life and what instrument is used to take readings?
Average time it takes for the number of nuclei in a radioactive isotope sample to halve. Geiger-muller tube
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What are the uses of radiation, name 4
Smoke detectors, Medical tracers, Radiotherapy and Sterilisation
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Explain all the uses of radiation in Smoke detectors, Medical tracers, Radiotherapy and Sterilisation
SD: alpha between two electrodes causes ionisation so current flows, smoke absorbs current and stops current. MT: injected or eaten, external detector tracks progress round body. R: kill cells, directed and moves. S: kills microbes, safe
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What is nuclear fission?
Splitting up of big atomic nuclei using uranium or plutonium rods, fired neutrons at it so split them up causing heat which produces steam, turns a turbine and spins a generator. This is a chain reaction.
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What is nuclear fusion?
Joining up of small atomic nuclei, releases lots of energy and little waste but needs high temperatures
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How is a protostar formed? How does this turn into a main sequence star?
clouds of dust and gas spiral together under the force of gravity. GE converted into HE, hydrogen undergoes nuclear fusion, outward heat pressure balances the force of gravity, enters a stable period.
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Explain the life cycle of a star about the same size as the sun
Red giant formed as hydrogen runs out so nuclear fusion of helium causes the star to swell, becomes unstable and ejects dust and gas as planetary nebula, hot dense core is a white dwarf which cools into a black dwarf, disappear
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Explain the life cycle of a star bigger than the sun
Red super giant formed, glow brightly again due to more fusion forming heavy elements like iron, explode in a supernova, throws layers of dust and gas into space, leaving a very dense core called a neutron star which will turn into a black hole
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Other cards in this set

Card 2

Front

What is radioactivity?

Back

Random process, unaffected by physical conditions, where the nuclei of atoms decay into other elements and give out radiation

Card 3

Front

Name the three sources of background radiation

Back

Preview of the front of card 3

Card 4

Front

State the 3 types of radiation and their properties

Back

Preview of the front of card 4

Card 5

Front

What is the definition of half life and what instrument is used to take readings?

Back

Preview of the front of card 5
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