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45 Cards in this Set
- Front
- Back
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What are the three different types of radiation? |
Alpha, beta and gamma radiation are the three types of radiation. |
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How ionising are alpha particles? |
Alpha particles are highly ionising and damage DNA. |
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How penetrating are alpha particles? |
Alpha particles are not very penetrative and can be stopped by a sheet of paper. |
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What structure does an alpha particle have? |
An alpha particle is made up of two protons and two neutrons. |
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What charge does an alpha particle have? |
Alpha particles have a 2+ charge.
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How ionising is beta radiation? |
Beta radiation is less ionising than alpha radiation but more ionising than gamma. Beta radiation has the ability to knock electrons out of atoms and form charged particles. |
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How penetrating is beta radiation? |
Beta radiation can penetrate air and paper. It can be stopped by a thin sheet of aluminium.
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What structure does beta radiation have? |
Beta radiation is a high energy electron.
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What is the mass of an alpha particle? |
The mass of an alpha particle is 4.
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What is the charge of a beta particle? |
Beta particles have a charge of 1.
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What is the mass of a beta particle? |
Beta particles have a mass of almost 0. |
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How ionising is gamma radiation? |
Gamma is the least ionising radiation out of the three. |
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How penetrating is gamma radiation? |
Gamma radiation is highly penetrative. It can only be stopped by 10 cm of lead or metres of concrete. |
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What structure does gamma radiation have? |
Gamma radiation is an electromagnetic wave. |
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What is the definition of background radiation? |
Background radiation is the radiation present in the environment. |
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How do you measure the radioactivity of a source? |
Use a Geiger counter to take background readings. Then take readings of the source and subtract the background reading. |
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Why do we need to take background radiation readings? |
We need to take background readings because the background radiation can be higher or lower in the same area. |
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What is the definition of half life? |
Half life is the time taken for the count rate of a radioactive sample to decrease by half. |
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What half life should medical tracers have? Why? |
Medical tracers should have a half life long enough to allow doctors to detect the radioactivity but short enough to reduce damage to cells. |
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What is a radioisotope? |
Radioisotopes are radioactive isotopes which have different uses. |
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What are the uses of gamma rays? |
Gamma rays kill living cells and penetrate materials so are used to sterilise equipment and for cancer treatments. |
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What are the uses of beta radiation?
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Beta radiation can penetrate thin sheets of metal and cardboard so can be used to find the thickness of materials. |
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How are radioisotopes with a short half life used? |
Radioisotopes with a short half life can be used as medical tracers as they do not stay in the body for too long and can find blockages, tumours and check blood flow. |
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What was the early model of the atom called? |
The plum pudding model. |
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Why did Rutherford start his experiments? |
Nobody knew for sure that the plum pudding model was accurate and he wanted to find out more about the structure of the atom. |
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What was the premise of Rutherford's experiments? |
Rutherford fired alpha particles at gold foil and observed the scattering of the particles. |
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What were Rutherford's main findings? |
Most particles passed straight through, some particles were deflected and a small number of particles were completely reflected back. |
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What did Rutherford's findings mean for the structure of the atom? |
As most particles past straight through, this meant the atom was made up of mostly empty space. As some particles were deflected, this meant there was an area of positive charge repelling the positive alpha particles. Few particles were completely repelled which meant there was a small region of concentrated charge and mass. |
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How do alpha and beta particles act on electric and magnetic fields?
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Alpha and beta particles have opposite charges so they are deflected in opposite directions by electric and magnetic fields. |
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What is the definition of nuclear fission? |
Nuclear fission is the splitting of a nucleus into two or more parts. This takes place in a nuclear power station.
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What are the fuels for nuclear fission? |
Uranium-236 and Plutonium-239 are the fuels used for nuclear fission. |
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What are the steps of nuclear fission? |
1) A slow moving neutron is fired at a uranium-235 or plutonium-239 nucleus and is absorbed, making it unstable. 2)It splits into two smaller nuclei as well as three more neutrons, releasing a vast amount of energy in the process. 3)The neutrons which were released are then split into two or three more nuclei which can start a chain reaction involving more atoms at each stage. |
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Why is a vast amount of energy produced during nuclear fission? |
A vast amount of energy is produced is due to the strong forces in the nucleus. |
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Why must the chain reaction during nuclear fission be controlled? |
If the chain reaction is not controlled it can result in an explosion. |
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How do you control a chain reaction? |
Control rods can be used which absorb surplus neutrons, slowing down the rate of the chain reaction. |
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What are the advantages of nuclear fission? |
1) A lot of energy is released per gram of fuel. 2) Fuel is widely available. 3) No greenhouse gases required. 4) Reliable |
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What are the disadvantages of nuclear fission? |
1) There is a risk of accidents releasing radioactive dusts and gases. 2) Radioactive waste cannot be eradicated and is usually buried which could leak or be dug up and contaminate the ground. 3) Nuclear power stations are expensive to build and decommission. |
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What is the definition of nuclear fusion? |
Nuclear fusion is the joining of two small nuclei forming a nucleus of a different element and releasing energy. |
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What release energy using nuclear fusion? |
Stars release energy using nuclear fusion. |
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How does nuclear fusion occur on the sun? |
The sun is made up of mostly hydrogen but the high temperatures on the sun make it possible for hydrogen atoms to fuse together to form helium. This process releases massive amounts of energy. |
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What types of elements are produced by nuclear fusion in stars?
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Elements lighter than iron are produced by nuclear fusion in stars. |
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When are elements heavier than iron produced? |
Elements heavier than iron are produced during supernova. |
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What are the advantages of nuclear fusion? |
1) The waste product of nuclear fusion is helium, a non-toxic gas that does not contribute towards global warming. 2) Hydrogen is easily obtained. 3) A huge amount of energy is released. |
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What are the disadvantages of nuclear fusion? |
1) It is not economically viable due to the high temperatures required. 2) We cannot currently sustain the temperatures needed to keep fusion happening. |
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How is a protostar formed? |
Dust and gases are pulled together by gravity. |
