Quantum Physics Made Simple

Radar Radar is an acronym for radio detection and ranging. It is a system used to detect, range (determine the distance) and map objects such as aircraft and rain. Strong radio waves are transmitted, and a receiver listens for reflected echoes. By analyzing the reflected signal, the reflector can be located, and sometimes identified. Although the amount of signal returned is tiny, radio signals can easily be detected and amplified. Radian The radian measure of the angle is the length of the arc cut out by the angle, divided by the circle’s radius. Therefore 2π radians is equal to 360° (a …

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Quantum Chromodynamics (QCD) Is the physical theory describing one of the fundamental forces, the strong interaction. It was first proposed in the early 1970s by Frank Wilczek and Dieter Gross. Quantum Electrodynamics (QED) Is a quantum field theory of electromagnetism. QED describes all phenomena exhibited by charged point particles, such as electrons and positrons, and the particles of light (photons), interacting by electromagnetism Quantum The smallest discrete amount of any quantity (plural: quanta). The word comes from the Latin for quantity. Electric charges comes in fixed multiples of a basic unit, the quantum of charge. Quantum Mechanics or Quantum Physics …

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Pauli Exclusion Principle The principle that no two particles in the same quantum state may exist in the same place at the same time. Particles that obey this principle are called fermions; particles that do not are called bosons. Photoelectric Effect Is the flow of electric current in a material or through a vacuum (as in a photocell) when the material is exposed to light. Although the effect itself had been known for some time, Albert Einstein first described how it was caused by absorption of photons, or quanta of light, in the interaction of light with the electrons in …

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Ockham’s Razor A premise in the philosophy of science due to William of Ockham which states that “entities should not be multiplied unnecessarily.” This is commonly interpreted to mean that the simplest of a set of competing viable theories is preferable. Olber’s Paradox If the universe has an infinite amount of stars then the sky should be infinitely bright. But many stars have been born, lived, and died already. Basically at any one time there are not enough stars active to fill the space of the Universe with enough radiation to light the night sky so therefore the sky is …

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Nanotechnology The development and use of devices that have a size of only a few nanometres. Considerable interest has been shown in the production of structures on a molecular level by suitable sequences of chemical reactions or lithographic techniques. It is also possible to manipulate individual atoms on surfaces using a variant of the atomic force microscope to make, for example, high density data storage devices. Also Known As: Nano Machines, micromachines, micro machines. The first mention of this technology was in a talk given by Richard Feynman in 1959. Neutrino A lepton with no electric charge. Neutrinos participate only …

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Mach’s Principle The inertia of any system is the result of the interaction of that system and the rest of the universe. In other words, every particle in the universe ultimately has an effect on every other particle. Named after Ernst Mach in 1893. Magnetopause The boundary of the magnetosphere, separating plasma attached to Earth from the one flowing with the solar wind. Magnetic Resonance Imaging (MRI) An imaging technique based on the principles of Nuclear Magnetic Resonance. Uses positrons to trace the structure of the brain using radioactive dyes injected into the patient. Maxwell’s Equations Maxwell’s equations are the …

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Lamb Shift There is a difference between the first two energy levels in the spectrum of hydrogen, this is called the Lamb Shift after the Willis Eugene Lamb. Law of Conservation of Energy/Momentum Energy/momentum cannot be created or destroyed; it may be changed from one form to another. Law of Universal Gravitation Gravitational force between two objects depends directly in the product of their masses and inversely on the square of their separation. Laser An optical device that produces very narrow beam of monochromatic (one wavelength), coherence (in the same phase) and intense light. It works by pumping electrons to …

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Kepler’s Laws Kelvin A The SI unit of temperature, it is a the temp, it is the fraction 1/273.16 of the thermodynamic temperature of the triple point of water. The triple point of water is the temperature at which water exits in all three states – solid, liquid and gas. Kaon There are two charged Meson K– and K+ and a neutral meson Ko in the K Meson family, these particles are collectively called kaons. They were the first particles to contain strange quarks. Kuiper Belt Is a disk-shaped region past the orbit of Neptune roughly 30 to 100 AU from the Sun …

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Josephson Junction Consists of two superconductors separated by a thin insulated layer, 1 to 2 mm thick. At normal temperatures a small current can flow between the conductors but at low temperatures the junction has no resistance. If a magnetic field or current is increased past a critical value then the zero resistance is lost and the cycle starts again. This means that the junction can be used to measure very weak magnetic signals or as extremely fast switched in supercomputers. Joule-Thomson Effect (Joule-Kelvin Effect) When a gas expands through a small hole this causes a change in temperature, the …

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Iconoscope A form of camera tube in which a beam of high-velocity electrons scans a photoemissive mosaic. It was invented by Vladimir Zworykin in 1923, and used in electronic TV broadcasting from 1939 until it was replaced by more advanced tubes. Inertia Is an object’s tendency to resist changes in its state of motion. Therefore if it is at rest or moving at a constant velocity, it takes a force to overcome the objects inertia. The measure of inertia is the objects mass. Interferometer An instrument that works on the principle that two waves that coincide with the same phase …

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