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Flashcards in P6 Deck (35)
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whta do you measure radioactivity with?

-Geiger counter


Whaty makes an atom radioactive?

-this is when the nucleus is unstable

-decays to become more stable

-emits energetic radiation


what are the three types of radiation and what are their properties?

alpha- goes a few centemeters in air, very penetrating

beta- less penetrating, goes 10-15 centemeters in air

gamma rays- most penetrating radiation, penetrates many meters




What did scientists know about atom's structure before?


- thought the atom was a solar system model



Describe Rutherford's experiment?


- Start with a metal foil. Use gold, because it can be rolled out very thin, to a thicknedd of just a few atoms.

- Direct a source of alpha radiation at the foil. Do this in a vacuum chamber, so that the alpha particles are not absorbed by the air

- Watch for flashes of light as the alpha particles strike the detecting material on the screen at the end of the microscope

- Work all night, counting the flashes at different angles, to see how much alpha radiation is detected.


What were Rutherfords observations?


- most particles went straight through 

-a few deflect by a few degrees

- small fraction completly deflected


What was the reason for Rutherfords oberservations?

-the nucleus is positive

- reason for deflecting radiation




What is an isotope?

- an isotope is a different type of an a element

e.g. carbon six proton

-can have different number od neutrons 

-e.g. carbon-11


-carbon 12 



How to nuclear equations work?


What are some specific details about alpha particles?

- haevier than beta particles 

- collide quickly with air molecules  and slow down 

- gain electrons to become helium atoms

- ionising but not penetrating


what are specific details about beta radiation?

=- fast moving electrons

- smaller than alpha, less likely to collide with air

- less ionising

- act like electrons when they slow down


What are some specific details about gamma radiation?

-released when a nucleus emits an alpha or beta particle and the atoms in the nucleus rearrange to a lower energy state

- does not change element

 - very penetrating

- very weak ionising


What is a use of ionising radiation?

-Food irradiation- Gamma radiation

- kills bacteria

- sterilising medical equipment

- kills bacteria

medical produces- Cancer

- smoke alarm

- exit signs

- nuclear weapons 

nuclear reactions


What are some sources of radiation?


-84% Natural

-16% Artificial


What are radiation units and what is the reccomended dose in the Uk?

-mSv- milli- seaverts


- if someones with dose of 100-mSv

-three out of a hundred will develop cancer

- can be exposed to cosmic rays 0.1mSv

when flying


What can affect a radiation dose?

- tupe of particles e. g. alpha- 20 dose

beta-1 dose

gamma rays- 1 dose

- alpha paticles are only hazards in the body

- damage depends on effected area 

- Radon gas. breathed in 

-can cause damage 

- dose is affected by

- time of exposure

-type of particles

- and amount body of material


Why ionising radiation dangerous?

- cause DNA molecules to behave abnormally

- Cells may form cancer

- one Radon atom can cause cancer


What is irradiation and what is the difference compared to contamination?

-exposure to radiation source to outside your body 

Danger scale: 1.gamma 2. beta 3. alpha

- contamination

- this when a source gets inside the body

Danger scale: 1.alpha 2. beta 3.gamma


What are some precautions to lower the radiation dose for radiation workers?

- use protective clothing and screens 

- wear gloves +aprons

-wear special devices to moniter their dose


Who discovered Radon and how does it effect the body?

- discover by georgius agricola a doctor

- noticed high death rate of german silver miners

- thought it was duie to breathing in dust

- high concentration of Radon in mines 

- radioactives -ionising

- causes lung cancer


How can radon build up its concentration?

- by being trapped in enclosed spaces


How many deaths a year does.......?



- with a population of 69 million in 2008


Describe graphs of radioactive activity and how to calculate the half-lfe?

-negative correlation between activity and time

- take a point high on the graph, they take half of it and on the activity axis. then subtract the t(1) from t(2)= half life


What is one use of gamma rays in medicine?

-medical imaging

- contaminates patients

- have to flush toilet multiple times

- wash hans thouroughly

- avoid close contact

- benefits outweigh the risks

- gamma rays can cause damagine to healthy cells


What is an example of radiotherapy?


- thyroid cancer

- swallowed- goes to thyroid naturally

and kills cells through beta radiation


What is an example of nuclear fission?


-when uranium splits releases a huge amount of energy

- can be calculated by E=mc(2)

- reaction controled by using rods of boron which absorb neutrons


What is a by product of nuclear fission?

- Plutonium can be used to make nuclear weapons


How are nucleuses held together?

- strong nuclear force

- atoms are at exactly the right distance apart 

-it is a balanced by electriacal force


What si nuclear fusion?


-isotopes repel eachother due to electrical force

- if they get close enough the attractive force brings them together

- takes a lot of energy to do this

- energy released- can be calculated by E=mc(2)

-products of the reaction 


why is fusion better than fission?

-less nuclear waste

- more fuel(water)