![]() When two objects are attracted to each other, we can imagine the exchange happening like this: When forces interact between two objects, an exchange particle is passed between them. ![]() The bosons or force carrier particles is discussed in the next section below. The particles in bold are NOT part of the course and will not be tested. The example interactions include attraction, repulsion, decay and annihilation.īelow is a table of their relative strengths and ranges. The universe exists upon four forces and interactions. This process is reversible, therefore a photon can produce a matter and an antimatter pair. This interaction conserves energy, momentum and charge.įor example, an electron and positron can annihilate each other to produce to photons. When matter and antimatter collide they annihilate each other and produce two photons. The energy of a photon can be calculated by the following relationship:Īs discussed all matter particles have antimatter pairs. Photon Model of Electromagnetic Radiation Notice how all antiparticles have a line drawn on top the symbol. Particles Antiparticles & PhotonsĪs discussed beforehand all particles have an antiparticle pair. In order to ensure that momentum was conserved, scientists predicted that a new particle was also being created and ejected. When beta decay occurs, there was some momentum that went missing and was unexplained. Neutrinos and antineutrinos were hypothesised due to the conservation law of momentum. It also has a new particle called an antineutrino Just like the alpha decay, beta decay also includes Q - the energy released in the decay. We will focus on the alpha and beta decay equations. These can take the form of either alpha radiation (helium nucleus) or beta radiation (an electron). The nucleus will release energy to become more stable and sometimes it will also release matter as well. It might have too many neutrons or too few (though this is very unlikely). This can be for a few reasons such as having too much energy or being large and heavy. Sometimes the nucleus can become unstable. It has a short range attraction up to 3 fm and a very short range repulsion closer than 0.5 fm. The strong force keeps the nucleus together and stable. We will focus on the strong force for now and return to the others in another learning episode. The strong nuclear force (also known as the strong force), the weak force, the electromagnetic force and gravity. There are four fundamental forces in nature. What is the specific charge of the calcium ion? Your answer should include: 4.8 / 106 Explanation: 4.8 × 106 C kg–1 Stable & Unstable Nuclei The units of specific charge is Ckg-1 What is the relative charge of a positron? 1 Explanation: +1 is correct! A calcium ion is formed by removing two electrons from an atom of 4020Ca. The specific charge of a particle is a ratio between the total charge and the total mass. This means that not all elements have the same number of neutrons, but they must have the same number of protons. If you need to work out how many neutrons there are in an atom then you need to minus the atomic number from the mass number or:Īn isotope is an element that has a certain number of neutrons. Sometimes the atomic number is also called the proton number. The constituents of atoms are shown in a particular way known as nuclide notation.Īs above, the mass number is both protons and neutrons and the atomic number is just protons. When a matter particle and antimatter particle meet, they annihilate into pure energy! The anti-matter pair of an electron is called a positron. Gravity affects matter and antimatter the same way because gravity is not a charged property and a matter particle has the same mass as its antiparticle. For instance, a proton is electrically positive whereas an antiproton is electrically negative. This is because the charge from all of the protons combined ‘cancels out’ the overall charge from all of the electrons.įor every type of matter particle we’ve found, there also exists a corresponding antimatter particle, or antiparticle.Īntiparticles look and behave just like their matter particle counterparts, except they have opposite charges. This means that the overall charge of an atom is zero or neutral. The key information for subatomic particles are shown in the table below.Īn atom normally has the same number of protons and electrons. Electromagnetic Radiation & Quantum Phenomena.
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