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Descrição
FlashCards por Daniella Giannitto, atualizado more than 1 year ago
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Criado por Daniella Giannitto
mais de 9 anos atrás
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| Questão | Responda |
| What holds the nucleus of an atom together? | The strong force. |
| What is the periodic table? | A table of elements, which are the simplest materials. |
| What in an atom determines the type of element? | The number of protons. |
| What is are isotopes? | Elements that are the same as they have the same proton number, but a different number of neutrons. |
| What can be used to detect radiation? | A Geiger Counter. |
| Where does radioactivity come from in a material? | The nucleus. |
| Explain Ionisation by Radiation. | 1. Materials are made up of chemical molecules (atoms). 2. Molecules absorb energy from photons that strike the material. 3. If a photon is ionising radiation, it contains enough energy to split the molecule. 4. The molecule is split into electrons and positive ions. These charged particles trigger chemical reactions. If this occurs in DNA it can be harmful - mutation, cancer, etc. |
| Describe an Alpha radiation particle. | ☺alpha particles are helium nuclei. ☺have 2 protons and 2 neutrons. ☺ mass of 4, charge of +2. ☺big, heavy, slow. ☺can't penetrate materials or travel far through air. ☺strongly ionising. |
| Describe Beta radiation particles. | ☺beta particles are electrons. ☺no mass, charge of -1 ☺quite fast and quite small. ☺penetrates through some materials, air range = 10-15cm ☺for every beta particle emitted a neutron turns to a proton in the nucleus. |
| Describe Gamma radiation photons. | ☺are photons. ☺after spitting out an alpha or beta particle the nucleus may need to get rid of extra energy. ☺it does so by emitting a gamma ray - an electromagnetic wave. ☺penetrates far into materials, air range = many metres. ☺purely energy, so doesn't change the nucleus of the element that emits it. ☺ |
| Draw a basic penetration power diagram for these types of radiation. | |
| What is alpha decay? | When an alpha particle is made it takes 2 protons and 2 neutrons from the nucleus of the atom, causing the element to change into a different one. |
| What I beta decay? | When a beta particle is made it turns a neutron in the atom into a proton, causing the element to become a different one. |
| Draw a diagram to show the scattering of alpha particles. | |
| What is a half-life? | 1. the time it takes for the number of nuclei of the isotope in a sample to halve. 2. the time it takes for the count rate from a sample containing the isotope to fall to half its starting level. |
| What is contamination? | Coming into contact with radiation. e.g. inhalation, ingestion, touching it... |
| What is irradiation? | Being exposed to radiation without coming into contact with it. |
| What is radiation dosage measured in? | Sieverts (Sv) or Millisieverts (mSv) |
| What is the pattern of radioactive decay? | The pattern is completely random and it is impossible to predict when an isotope will decay. |
| What is the pattern of the decay of radioactive materials? | The pattern is regular and the activity decreases as it happens. The time taken for half an isotope to decay is called a half-life. |
| What is nuclear fission? Use the example of Uranium in a power plant. | A neutron is fired at the nucleus of a Uranium-235 atom and the nucleus splits. 2 smaller nuclei are formed and 3 neutrons are fired out. these fragments carry energy that heats the reactor a lot more than a chemical reactor, the new neutrons released could hit another U-235 atom and cause more fission. this releases more energy and starts a chain reaction. |
| What happens inside a nuclear reactor. | Nuclear fission occurs inside uranium rods, stored in a sealed reactor. A liquid called coolant is heated in the reactor and is passed into the boiler to heat water. The chain reaction is moderate using control rods that absorb neutrons. The more control rods are lowered into the reactor, the more neutrons they absorb and can slow down or even stop fission. |
| Draw a sketch of a nuclear reactor. | |
| What is nuclear fusion? | Nuclear fusion releases a large amount of energy, even in comparison to fission. the waste products are nearly harmless. Energy production by fusion has not yet been artificially achieved because large temperatures and pressures are needed to force hydrogen atoms to release their electrons, become a plasma, and overcome electrostatic repulsion. |
| What are the products and reactants of hydrogen fusion? | Reactants: Tritium and Deuterium. Products: Helium, Neutron. |
| What is released during fusion and fission? | Energy. |
| How can energy be calculated? |
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