Radioactivity Flashcards
Who discovered two types of Radiation
Ernest Rutherford
Who were Ernest Rutherford’s workers
Hans Geiger and Ernest Marsden
What are the three types of radioactivity?
Alpha radiation (α), beta radiation (β) gamma radiation (γ).
What is activity?
Activity is the number of decays in 1 second of a source
Which type of radiation is the most penetrating?
Gamma radiation.
Why is beta radiation dangerous??
Because it has moderate ionising powers and moderate penetrating powers.
Which type of radiation cannot be penetrated by paper?
Alpha radiation.
What can ionising in a living cell do?
It can damage or kill the cell.
Can beta radiation penetrate paper?
Yes
Why are some substances radioactive?
Atoms that have an unstable nucleus try to become stable and in the process emit radiation.
Name 2 uses of radiation
Any 2 below:1.Treating cancer 2.Sterilising medical instruments 3.Sterilising food4.Detecting brain tumours
Where is most of an atom’s mass located?
The small, positively charged nucleus.
what is ‘Half Life’?
Half life is the average time taken for the number of nuclei of the isotope in a sample to half.
What did the scientists think the atom was like in 1914?
Plum Pudding.
Which type of radiation was stopped by paper?
Alpha radiation
What was the name of the Physicist who discovered that alpha and beta radiation is made up of different types of particles?
Ernest Rutherford.
What are the 3 conclusions Rutherford made after his scattering experiment?
- Atoms are made up of empty space
- The nucleus is positively charged therefore it repels the positive alpha particles
- The atom must have a very small dense nucleus in the middle
What is a alpha particle made up of?
Two protons , two neutrons
Which radiation is the most dangerous in terms of ionising?
alpha
Which scientist carried out experiments where we put different materials between the radioactive substance and a detector.
Ernest Rutherford
Which of the following are made up of different types of particles? Alpha, beta or gamma
Alpha and bae
Which type of radiation is the least ionising?
Gamma.
What was the proposed model of the atom before it was discovered called?
The plum pudding model.
Define Ionising
When radiation knocks an electron off an atom. This results in very reactive positive atoms.
When was the nucleus discovered ?
1914
what are the three types of radiation?
Alpha, Beta and Gamma
What is the rough range of alpha radiation in the air?
5 cm
What is the relative mass of a proton and neutron?
1
What is the relative charge of a proton?
1
What are the three types of radiation?
Alpha,Beta,Gamma
What is the relative charge of an electron?
-1
which types of radiation ionise substances they pass through?
alpha, beta and gamma radiation
What type of radiation is the most ionising?
Alpha.
Why are some substances radioactive?
Because their nucleus is unstable so it emits either alpha, gamma or beta radiation
What is it called when atoms become charged because they lose an electrons?
Ionisation
What is the rough range of alpha radiation in the air?
5cm
What particles make up alpha radiation?
Two protons and two neutrons. It is identical to a helium nucleus.
Which 3 of the different types of radiation is stopped by paper?
Alpha Radiation
What is the rough range of beta radiation in the air?
1 m
what does ionisation in a living cell do to the cell?
Can damage or kill the cell
What is the range of gamma radiation in the air?
Unlimited- spreads out in air without being absorbed
What counter can you use to detect radioactivity?
A Geiger counter
Can alpha radiation penetrate paper?
No
What material stops beta radiation?
Aluminium
Why would you store a radioactive source in a lead-lined box?
Because it cannot be penetrated, even by gamma radiation.
Can you predict radioactive decay?
No
Who discovered the neutron and when did they discover it?
James Chadcick 1912
What particle does beta radiation emit?
A single electron. This has a mass of zero and a charge of -1.
What could the ‘plum pudding’ model not explain?
Why some alpha particles were scattered through large angles
What’s more penetrating gamma or beta?
Gamma
Name 3 ways of reducing radiation exposure.
- Keeping as far away as possible from the source of radiation- Sending as little time as possible in at-risk areas- Shielding yourself by staying behind thick barriers, using thick lead plates and wearing protective clothing.
What is radiation?
The emission of energy as electromagnetic waves or as moving subatomic particles, especially high-energy particles which cause ionization.
Which type of radiation consists of electromagnetic radiation?
Gamma radiation.
What is irradiation?
Radiation outside of one body causes ionisation, the irradiated object does not become radioactive.
What is an isotope?
How are isotope related to radioactivity?
Isotopes are atoms that have the same number of protons but a different number of neutrons
Isotopes are related to radioactive becuase some isotopes of an element are stable and others are not stable. This means that some of them are radioactive and others are not
How do you calculate the half life of a substance from a graph.
Example: What is the half life of this radioactive isotope?
To find the half life from a graph you need to work out what half of the starting ammount is. You then look at the time when the number of nuclei have reached this number
You can check it by halfing it again, and looking at the time it has taken to half a second time.
