Radioactivity Flashcards
The radiation that will be stopped by a layer of skin/ sheet of paper is
Alpha radiation
____ and ____ radiation can pass through sheets of paper but only ___ can pass through a few mm of aluminium.
Beta
Gamma
Gamma
The radiation that will be stopped by a thin layer of aluminium is
Beta
In a nuclear power station energy is released from changes in the _____ of the atoms of the nuclear fuel (uranium)
Nucleus
Adding electrons to an uncharged atom makes it
A negative ion
If a ____ source is placed inside a patient for medical reasons most of the radiation emitted will pass through the body
Gamma
Removing electrons from an uncharged atom makes it
A positive ion
The used fuel from a nuclear reactor is ____ and radioactive when it is removed from the reactor. After it has cooled, it has to be stored in ____ containers for ____ years because it contains radioactive isotopes with ____ half lives.
Hot
Sealed
Many
Very long
An alpha particle is emitted by an unstable nucleus that has ____ protons and neutrons. The nucleus ____ 2 protons and 2 neutrons when the alpha particle is emitted.
Too many
Loses
Measurements from alpha scattering experiments prove that an atom has a small ____ charged nucleus where most of the ____ of the atom is located.
Positively
Mass
How is the chain reaction in a nuclear reactor controlled?
By the moderator made of graphite, and also by raising and lowering the control rods.
Alpha radiation causes the most damage for every mm it passes through cells. Why is alpha radiation relatively safe as long as the source is outside your body? What if it is inside your body?
Alpha radiation is absorbed by the dead skin cells of your outer skin layer. If ingested, it would definitely be absorbed by your body, causing damage.
Alpha is least penetrating because it is ____ and _____.
Heavier and slower
The most penetrating is
Gamma
Alpha radiation is one form of ionising radiation. What are the other two main types?
Beta and Gamma
A proton has a ____ charge. An electron has an equal ____ charge. Neutrons are ____.
Positive
Negative
Neutral
Isotopes are atoms of the same element with different numbers of
Neutrons
How is the energy released in the nuclear reactor made to drive a turbine?
The energy released in a nuclear reactor heats up the coolant, which heats water and evaporates it into steam. The steam then turns the turbine.
The protons and neutrons make up the ____ of the atom. ____ move about in the space round the nucleus. An uncharged atom has equal numbers of ___ and ____.
Nucleus
Electrons
Protons and Electrons
Atoms of the same element have the same number of _____.
Protons
The least penetrating radiation is
Alpha
The most penetrating radiation is
Gamma
The radiation with the shortest range in air
Alpha
An alpha particle consists of _____ protons and _____ neutrons.
Two
Two
The unit radioactivity is measured in is
Becquerel, or counts per minute
A beta particle is a fast moving ____.
Electron
What would this become if it emitted a beta particle?
238 /\ /
93 / \/ p
238 P
94 | U
Plutonium
What would this become if it emitted an alpha particle?
238 /\ /
93 / \/ p
236 P
91 | A
Protactinium
Who did an experiment with alpha particles and gold leaf?
Geiger and Marsden
If 1/64th of a sample is still radioactive, how many half lives have passed?
Six
How could you detect ionising radiations?
Geiger-Muller counter
or
Photographic film
How much of a sample is left if 9 half lives have passed?
1/512th
Describe how an ionising radiation monitoring badge works
The photographic film at the back is exposed by ionising radiation. One area is covered by card and aluminium and so only detects Gamma, one area is covered by card and detects Beta and Gamma and the third area detects all three.
If 1/32th of a radioisotope is left, and 35 hours have passed, how many half lives have passed? How long is one half life?
5 half lives
7 hours
Which is the nucleon number?
238 /\ /
93 / \/ p
238
What are the dangers of using ionising radiation?
- Cause mutations, including cancers
- Can damage cells and tissue, serious exposure can give radiation sickness
What is the atomic number?
238 /\ /
93 / \/ p
93
In the Geiger Marsden experiment, what factors affect the deflection of the alpha particles?
Charge and speed
What is half life?
The time it takes for the level of radioactivity to halve
What are the main sources of background radiation?
Radon gas, rocks and buildings, food and drink, cosmic rays, medical equipment
List some safety precautions that can be taken when using ionising radiation
- Reduce exposure
- ALARA- keep your dose As Low As Reasonably Achievable
- Lead shielding- lead glass, lead walls, lead aprons
- Monitor exposure
If a half life is 3 days and there is 1/1024th left, how much time has passed?
30 days
What is nuclear fission?
Nuclear fission is when the nuclei of Uranium are split by neutrons and releases energy.
