I don't get half life

  • 0 votes

can someone explain to me what half life is in simple word please ?

ive got so much qs 2 do but i don't even get it :( like how do u knw by looking at half life which one u are less likely to breathe in ????

help plzzz

Posted Thu 29th November, 2012 @ 16:53 by ? Secret - Team GR

13 Answers

  • 3 votes

if you mean half life in Physics, it is the time it takes for the number of (e.g Uranium) atoms to half in a substance (e.g a bar of uranium). to go into more detail, substances like Uranium "decay" which is when the smaller atoms to become more stable, as Uranium releases atoms (most likely an alpha particle- which is a helium atom) it changes into a different atom as it has a lower atomic number. This Ultimaately means that half life (in the case of Uranium) is the time it takes for the number of Uranium and only Uranium atoms in, say a bar of Uranium to decay/ cease to exist as Uranoum atoms. If you want you can think of it like there is a population of 100 people, in 50 years, there is a flood and it kills half of them, the half life in this case is 50 years as the population reached half at this time. Hope it helps :D

Answered Thu 29th November, 2012 @ 17:38 by Eamon Walker
  • 2 votes

there are 3 types of radioactive decay, alpha, beta and gamma, from order of highest penetration to lower it Gamma, beta and alpha. it works vice versa for ionising poewr, this is more dangerous to our body, those with the highest ionising power out of these (ie alpha) will be most damaging to our body as it makes the chemicals react differently (by knocking off electrons to create ions) and allows the cells to mutate into things such as cancer etc. so as Alpha has such a short half life, it releases all its energy quickly, which is why it has a high ionising power, since potassium has a longer half life, we can survive as it releases the energy slowly and does not do much damage, besides, we have like 0.0117% of our body so if it were harmful it would be so small and we get it naturally and is gennerally used for benificial purposes.

Answered Thu 29th November, 2012 @ 18:26 by Eamon Walker
  • 0 votes

yh sorry shldve mentioned its physics.. thnx i get it a bit more..

but for example, lets take potassium -40.. the half life is 1260 million years and decays by emitting beta particles.. how can we surivve by eating this isotope ??

Answered Thu 29th November, 2012 @ 17:50 by ? Secret - Team GR
  • 0 votes

thnx !!!!!

Answered Thu 29th November, 2012 @ 18:27 by ? Secret - Team GR
  • 0 votes

just for all reasons I did not get any of this info of the internet and was taught this, I am also learning this on GCSE level and just remember this stuff.

Answered Thu 29th November, 2012 @ 18:28 by Eamon Walker
  • 0 votes

with the potassium thing, were you testing me or was it a actual question?

Answered Thu 29th November, 2012 @ 18:33 by Eamon Walker
  • 0 votes

aww dw.. wether u did or didnt i dont mind.. thanks though for your help.. i just never understood the topic, n my teacher rushed through it.. but thanks anyway for explainin coz ur explanation was much more helpful XD

Answered Thu 29th November, 2012 @ 18:33 by ? Secret - Team GR
  • 0 votes

do you understand it now?

Answered Thu 29th November, 2012 @ 18:48 by Eamon Walker
  • 0 votes

this should help:

http://www.ndt-ed.org/EducationResources/HighSchool/Radiography/halflife1.htm

Answered Thu 29th November, 2012 @ 18:51 by Eamon Walker
  • 0 votes

yes i do understand it now dw.. thanks so much <3

n bwt the potassium thing.. it was an actual question .. dw i knw ur very smart :)

Answered Thu 29th November, 2012 @ 22:20 by ? Secret - Team GR
  • 0 votes

hi Eamon Walker, or anybody else :) do u knw anywhere were i cld get past exam questions on half life.. like the questions which ask u to do half life calculation coz i really need to practise..

the board im doin is new.. so they hve none :( dw if u cant.. thnx..

Answered Fri 30th November, 2012 @ 19:58 by ? Secret - Team GR
  • 0 votes

you are welcom for the help, sorry I do not know where you can get a question on half life except by asking ur teahcer or looking online :/

Answered Fri 30th November, 2012 @ 20:16 by Eamon Walker
  • 0 votes

okay thnx.. google doesnt seem to help.. so i guess ill just ask my teacher :)

Answered Sat 1st December, 2012 @ 13:32 by ? Secret - Team GR