all of p8

what is carbon 14

carbon 14 is a radioactive isotope

whats radioactive decay

radioactive decay is when some isotopes have an unstable nucleus,to become stable nucleus gives out radiation

what type of procss is radioactive decay?

radioactive decay is a totally random process

whats activity

activity is the rate at which a source of unstable nuclei decay

whats activity measured in

activity is measured in Bq becquerel

how many bq = 1 decay per sec

1bq=1decay per sec

what object do you use to measure activity

geiger muller tube

count rate

the count rate is number of decays recorded each second by a detector

what do alpha particles consist of,whats it the same as

alpha particles consist of 2 protons 2 neutrons so its the same as a nucleus of a helium atom

whats a beta particle

whats it ejected from

a beta particle is a electron ejected from the nucleus at very high speed,beta partcile formed inside the nucleus when a neutron changes into a proton and electron

what is gamma rays a type of?

gamma rays are type of electromagnetic radiation from the nucleus

4 types of radiation

alpha,beta,gamma,neutron

size of alpha,range iin air for alpha particles,

alpha particles are large,they can travel 5cm in air before colliding with air particles and stop

range iin air for beta particles,

beta particles travel further,reach 15cm in air before stopped

range iin air for gamma particles,

gamma radiation travels several meters in air before stopping

penetrating power- alpha particles

alpha particles stopped by single sheet of paper,

penetrating power- beta particles

beta particles stopped by few mm of aluminium,

penetrating power- gamma particles

gamma radiation stopped by several cm of lead

when radiation collides with atom

when radiation collides with atoms,it causes the atoms to lose electrons and form ions

ionising power of alpha

alpha particles very strong ionising

ionising power of beta

,beta particles quite strongly ionising,

ionising power of gamma

gamma radiation weakly ionising

what do radiactive isotopes release

radiactive isotopes release radiation from the nucleus of their atoms,

why scientists cant predict when nucleus decays

scientists cant predict when nucleus decays as the decay is a random process

whats half lfie

the half life of a radio active isotope is half the time it takes for the number of nuclei of the isotope in a sample to halve

whats half life in term of count rate

the half life is also time taken for the count rate or activity from a sample containing the isotope to fall to half its initial level

radiactiove isotope has half life of 15 days an inistal count rate of 200 counts pr sec determine the count rate after 45 days

45/15 =3

half 200 3 times

200/2, 100/2,50/2=25

radioactive isotopes do what from their nuclei

radioactive isotopes emit and decay radiation from their nuclei

what does ionising radiation cause

ionising radiation can increase risk of cancer in humans

whats irridation

irraditation is exposing an object to nucler radiation (alpha,beta,gamma,neutrons)

one precautiion to protect against alpha radiation

one precaution is sheilding- gloves can protect against alpha radiation

how can beta and gamma radiation can be reduced

beta and gamma radiation can be reduced by using lead apron

another sheilding

lead walls,lead glass screen protect us from it

radiation monsiter

radiation monitor measures how much radiation received

what do we do if someone received to much radiation

if someone received to much radiation we can stop them from working with raidoactive isotopes

radioactive contamination

radioactive contamination when unwanted radioactive isotopes end up on other materials

why radioactive contamination is hazardous

radioactive contamination is hazardous cuz radioactive atoms decay and emit ionising radiation

how hazardous is alpha radiation

its strongly ionising but easily stopped by dead cells on skin surface,alpha emmiters can be dangerous if inhaled or swallowed

how hazardous is beta radiation

beta radiation is quite ionising so penetrates into the body

how hazardous is gamma radiation

gamma radiation is weakly ionising penetrates the body but likely to pass straight through

whats peer review

scientists explored effects of radiation on humans,they are published and shared with other scientists to alllow findings to be checked

2 natural resourcesof backround radiation

radioactive rock,

cosmic rays from space,

2 manmade resourcesof backround radiation

fall out from nuclear weapons testing,

nuclear accidents

radiactive rock

certain rocks are radiactive like granite cornwall in uk this can be major source of background radiation

cosmic rays

cosmic rays are very high energy particles that travel through space and crash into the earths atmosphere

fall out from nuclear weapons testing,

nuclear weapons testing released radioactive isotopes into the environment for decades

nculear accidents

radioactive isotopes are released by accidents at nuclear power stations

your exposure to background radiation is affected by 2 things

your exposure to background radiation is affected by location and job for e.g

in cornwall they have ltos of granite

airline pilots exposed to high levels of cosmic radiation

dose of radiation measured what

dose of radiation measured in sv

to checkfunction of throid gland,paitent does waht

to checkfunction of throid gland,paitent drinks solution of radioactive iodine

radiaciotve iodine emits what and then

radiaciotve iodine emits gamma radiation and passes out of the body and can be detected

if the scan showsthe thyroid too much or little absorbed iodine what do doctors do

if the scan showsthe thyroid too much or little absorbed iodine ,doctors use this to diognose the paitents condition

1st step of using tracer

tracer must emit radiation that can pass out the body and be detected

2nd step of using tracer

the tracer must not be strongly ionising to minimise damage to body tissue

1st step of using tracer

the tracer must not decay into another radioactive isotope

last step of using tracer

the tracer must have a short half life so its not present in the body for along time

what radiotherapy

certain cancers can be destroyed using ionising radiation this is radiotherapy

how is radiotherapy process

gamma rays pass into the body,destroys the tumour

radiotherapy con

healthy issue may be damaged as radiation passes through the body

e.g of radiactive in the body instead of out: a paitent has radiactive rods inserted in his body to treat prostate cancer advantage.benefit

the radiation targets precisily to the tumour so less damage to healthy tissue

when a uranium nucleus absorbs a neutron it triggers the nuclus to undergo fission(split),

when the nucleus splits it forms 2 smalleer nuclei (daughter nuclei)

it emits 2 or 3 neutrons and gamma radiation,energy released during the fission reaction,all fision products have kinetic energy

neutrons can now be absorbed by more uranium nuclei and trigger fission again which is a chain reaction

a controlled chain reaction is used to release what and whats the explosion in a nuclear weapon is caused by

a controlled chain reaction is used to release energy in a nuclear reactior

,the explosion in a nuclear weapon is caused by an uncontrolled fission chain reaction

whats nuclear fusion

in nucleear fusion 2 light nuclei like hydrogen join to form heavier nucleus some mass of nuclei convert to energy which is released as radiation

what is nuclear fusion not?

nuclear fusion is not a chain reaction but fission is