Radiation Flashcards
What are the different types of ionising radiation
- Alpha
- Gamma
- Beta
Describe alpha radiation
- helium nucleus. 4 on the top and 2 on the botttom. Mass and atomic number
- low penetrating (1cm or 2cm in air)
- Deflects in a magnetic field
- stopped by papper
- very high ionsising
Decribe beta radiation
- Its an electron. 0 on the top and -1 on the bottom. With a negative charge
- low-ish penetrating power (1m in air)
- defelects in magnetic field
- stopped by 5mm of aluminium
- medium ionising power
Decribe gamma radiation
- it’s a wave. 0 on top and bottom
- almost infinite penetrating power
- doesn’t deflect in magnetic field
- stopped by 5cm of lead or 1m of concrete
- low ionising
What is halflife
The time it takes for the total number of radioactive atoms in a sample to decrease by half
What does an atom look like
Protons and neutron in the nucleus (centre) and electrons orbitting in shells around it
What are the uses of radiation
- gamma-emmitter can track blood flow or highlight gas leekages
- carbon dating (how old things are by amount of radiation in them)
- Radiotherapy (destroying cancer cells)
What is decay
When an unstable atom loses mass or energy
What is an isotope
Atoms with the same number of protons but a different number of neutrons
What is ionisation
The addaition or removal of electrons in an atom to become more stable
What is nuclear radiation
The energy or particles from a radiactive nucleus
What are the conclusions from rutherfords expeeriment and why
- some particle were undivieated: Atoms are mostly empty space
- some particles were rebounded: Atoms contain a small and heavy nucleus
- some particles were deflected but still coninued: Atoms Nucleus has a strong positive charge
What was Runterfords experiment
- in 1912
- shoot alpha particles at thin sheet of gold
- see how the particles travel
Is alpha radiation dangerous
- it ionises with the first 1cm-2cm air infront of it before it reaches you and can be stopped by paper
- however if inside your body it can make you ill and kill
Describe the plum pudding model
- It is a sphere of positive charge with negative electrons embeded. Like a plum pudding
- Helped us understand charge
Describe rutherfords model
We now have a nucleus in our atoms and understand them much better
Describe bhor’s model
- a nucleus being orbitted by shells of electrons
- helps us understand energy levels and electron orbiting
How do you work out neutrons
Nucleons(top number) MINUS protons (bottom number)
What is radioactive activity
The number of emissions per second
What is the similarity and difference between nuclear radiation and light
Similar: Both are radiated and absorbed
Differ: Radiation is ionising
How do you detect radiation
- geiger Muller Tube
- Photographic film
What can radiation be
Particles and waves
Why can’t we say when a nucleus will decay
Because the process is random
Nuclear radiation is emitted from where?
The nucleus
How do you calc the activity of a source
- turn the time into seconds
- divide the particles it emits by those seconds
What is the mass number
The top number (protons + neutrons)
What is the atomic number
The central bottom number
What is an ion
An atom that has lost one or more of its electrons.
What is Radioactive decay
Radioactive decay is the emission of energy in the form of ionizing radiation
What is contamination
Radioactive particles Getting onto or into an object
What do you need to be careful of when working with radiation
- exposure and physical contact with radioactive substances
What are the risks with radioactive materials
- Ionising radiation can enter living cells and ionise with them.
- This damages them (killing them or causing cancer)
What is irradiation
Exposure to radiation, we are always being irradiated by background radiation. Irritating something doesn’t make it radioactive.
Why is contamination dangerous
- the contaminating atoms might decay and release radiation
- Can harm you if it gets inside your body.
How does the different radiation types cause harm in Irradiation
- Outside the body beat and gamma are the most dangerous because they can be emitted and penetrate the body and reach your organs.
- ## Alpha is the least dangerous because of its low penetration levels
How does the different radiation types cause harm in contamination
- alpha is the most dangerous because they can do all their damage in a localised area
- Beta is less damaging because it’s radiation is absorbed over a wider are, and some passes out of the body all together
- Gamma sources are the least dangerous because they mostly pass straight out due to them having the lowest ionising power.
What is background radiation
The radiation that exists around us all of the time. It is from either natural or artificial sources.
