45264
Descrição
Mapa Mental por jessica-gollop, atualizado more than 1 year ago
|
Criado por jessica-gollop
mais de 11 anos atrás
|
|
Half life
- The unit for measuring radioactivity is
the becquerel (Bq). 1 Bq means one
nucleus is decaying per second.
- The radioactivity of a sample always
decreases over time (half life).
- HALF LIFE IS THE AVERAGE TIME IT TAKES FOR THE
NUMBER OF NUCLEI IN A RADIOACTIVE ISOTOPE TO HALF.
- In other words its the time it takes for the
count rate for a sample containing the
isotope to fall by half its initial level.
- In other words its the time it takes for the
count rate for a sample containing the
isotope to fall by half its initial level.
- When radioactive decay occurs an alpha, beta or
gamma particle is released. This means that one
more radioactive nucleus has disappeared.
- As the unstable nuclei all steadily
disappear, the activity (the number of nuclei
that decay per second) will decrease.
- So the older a sample becomes
the less radiation it will emit.
- So the older a sample becomes
the less radiation it will emit.
- How quickly the activity
drops off varies a lot.
- For some substances it takes just a few microseconds
before nearly all the unstable nuclei have decayed, for
others it can take millions of years.
- For some substances it takes just a few microseconds
before nearly all the unstable nuclei have decayed, for
others it can take millions of years.
- A short half life means the
activity falls quickly, because
lots of nuclei decays quickly.
- A long half life means the activity
falls slower because most of the
nuclei don't decay for along time.
- HALF LIFE IS THE AVERAGE TIME IT TAKES FOR THE
NUMBER OF NUCLEI IN A RADIOACTIVE ISOTOPE TO HALF.
- Do half life question step by step
- A typical question: The activity of a
radioactive isotope is 640 cmp
(counts per minute). Two hours later is
has fallen to 80 cpm. Find the half life.
- A typical question: The activity of a
radioactive isotope is 640 cmp
(counts per minute). Two hours later is
has fallen to 80 cpm. Find the half life.
Quer criar seus próprios Mapas Mentais gratuitos com a GoConqr? Saiba mais.