Radioactivity - Atomic Structure Physics Flashcards
What is used to detect radioactive decay?
Geiger-Muller tubes
What happens to an object that has been exposed to ionisation?
It is irradiated not radioactive
What is radioactive contamination?
Unwanted presence of materials containing radioactive atoms on other materials
What can ionisation do to a living cell?
Damage/kill a cell
Which radiation is more dangerous to the body?
Alpha radiation because it has the highest ionising power
State 3 ways to reduce ionising exposure
- Keeping far away
- Spending little time in environements that are ionising
- Shielding - thick concrete barriers
Explain how Ruthford observations support that the alpha particles deflected
Most of the mass and charge are concentrated in the nucleas.
Explain how Ruthford observations support that the alpha particles went straight through
The particle was mostly of empty space
Suggest one way our bodeis are radioactive
Becuase of the food we eat
Why is a radioactive source kept in a lead box?
Lead absorbs the radiation
Why isnt gamma radiation affected by magnets?
Gamma radiation has no charge so it doesn’t deflect. It isn’t affected
Why is gamma radiation used in a radioactive tracer?
- Less ionising
- Less dangerous
6 reasons why scientists keep a scientific journal for their findings
- Newspapers distort the facts,
- It has to be peer reviewed before being published
- becomes part of the scientific record
- other sicentists can develop or include their work
- one of the ways communities of scientists find out whats going on in their field
- establishes their research as credible in the eyes of their peers and the public
Explain how the distance at which an electron orbits the nucleas may be changed.
Electrons may absorb electromagnetic radiation and move further from the nucleas to a high energy level.
Energy level which are further from the nucleus are at a ________ than those which are closer to the nucleus
high energy
Where does background radiation come from?
Naturally occurring unstable isotopes like food, rocks, buildings
Radiation from space - cosmic rays from Sun, earth’s atmosphere protects us from it
Human activity - nuclear explosions and waste
How can you prevent contamination?
Gloves and tongs and protective suits
What sources are more dangerous outside the body and why?
Beta and gamma , highly penetrating and can damage organs
Which source is the most dangerous inside the body and why?
Alpha, highly ionising and they do all their damage is a very localised area
What does a short half life mean?
Activity falls quickly cuz nuclei are v unstable and rapidly decay, they are dangerous cuz of the high amount of radiation they emit at spread start but they quickly become safe
What does a long half life mean?
Activity falls more slowly cuz most of the nuclei don’t decay for a long time, source releases small amounts of radiation for a long time, can be dangerous cuz nearby areas exposed to this for millions
what is radioactive decay
isotopes with unstable nucleus give out radiation to become stable
what is activity? units?
rate at which a source of unstable nuclei decay in becquerel (Bq)
