Physics attempts to describe the fundamental nature of the universe and how it works, always striving for the simplest explanations common to the most diverse behaviour. For example, physics explains why rainbows have colours, what keeps a satellite in orbit, and what atoms and nuclei are made of. The goal of physics is to explain as many things as possible using as few laws as possible, revealing nature's underlying simplicity and beauty. Physics has been applied in many industrial fields, which include the air industry, construction industry, automobile industry, manufacturing industry and many others. All these industries apply physics in one way or another. For example a car that moves from one point to another has to have an engine that provides the momentum. The calibration of the engine together with the combustion of the fuel has to have a mechanical force that will move it.
Physics has helped shape the industries in making work easier. This will be highlighted with some of the industries that have used physics practically to achieve an objective.
Power generation industries
Physics behind solar Power Generation in Space shuttles
Solar arrays produce electrical power directly from sunlight. According to Green (1982), most long-duration space missions use solar arrays for their primary power. Most designs use photovoltaic cells to convert sunlight into electricity. They can be made from crystalline silicon, or from advanced materials such as gallium arsenide (GaAs) or cadmium telluride (CdTe). The photovoltaic cells with the highest efficiency use several layers of semiconductor material, with each layer optimized to convert a different portion of the solar spectrum. The solar intensity at Earth's orbit is 1,368 watts per square meter, and the best photovoltaic cells manufactured today can convert about a third of the solar energy to electrical power. For electrical power when the Sun is not available (for example, when a space vehicle is over the night side of Earth), solar power systems typically use rechargeable batteries for storage.
According to Glaser, Davidson, and Csigi (1993), solar power systems can also be designed using mirrors or lenses to concentrate sunlight onto a thermal receiver. The heat produced by the thermal receiver then is used in a heat engine, similar to the steam turbines used in terrestrial power plants, to produce power. Systems of this type can store power in the form of heat, instead of requiring batteries, but have not yet been used in space.
Nuclear power in space shuttles
Since solar power decreases with the square of the distance from the Sun, missions to the outer planets require an alternate power source. Green (1982) indicates that nuclear power systems can provide power even when sunlight is unavailable. Nuclear generators are categorized as "radioisotope" power systems, which generate heat by the natural radioactive decay of an isotope, and "reactor" power systems, which generate heat by a nuclear chain reaction. For both of these power systems types, the heat is then converted into electrical power by a thermal generator, either a thermoelectric generator that uses thermocouples to produce power, or a turbine. For radioisotope power systems, the most commonly used isotope is Plutonium-238. The plutonium is encapsulated in a heat-resistant ceramic shell, to prevent it from being released into the environment in the case of a launch accident. Such isotope power systems have been used on the Pioneer, Voyager, Galileo, and Cassini missions to the outer planets (Jupiter and beyond), where the sunlight is weak, and also on Apollo missions to the surface of the Moon, where power is required over the long lunar night.
Physics behind airplanes
Air travel is one of the great triumphs of the 20th century. Every day hundreds of thousands of people are carried through the air to destination all around the world. In every case the flight of...
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