Modern physics is a branch of physics that developed in the early 20th century and onward or branches greatly influenced by early 20th century physics. Notable branches of modern physics include quantum mechanics, special relativity and general relativity.
Classical physics is usually concerned with everyday conditions: speeds are much lower than the speed of light, sizes are much greater than that of atoms, yet very small in astronomical terms. Modern physics, however, is concerned with high velocities, small distances, and very large energies.
Classical physics is typically concerned with everyday conditions: speeds are much lower than the speed of light, sizes are much greater than that of atoms, and energies are relatively small. Modern physics, however, is concerned with more extreme conditions, such as high velocities that are comparable to the speed of light (special relativity), small distances comparable to the atomic radius (quantum mechanics), and very high energies (relativity). In general, quantum and relativistic effects are believed to exist across all scales, although these effects may be very small at human scale. While quantum mechanics is compatible with special relativity (See: Relativistic quantum mechanics), one of the unsolved problems in physics is the unification of quantum mechanics and general relativity, which the Standard Model of particle physics currently cannot account for.
Modern physics is an effort to understand the underlying processes of the interactions of matter using the tools of science & engineering. In a literal sense, the term modern physics means up-to-date physics. In this sense, a significant portion of so-called classical physics is modern.[1] However, since roughly 1890, new discoveries have caused significant paradigm shifts:[1] especially the advent of quantum mechanics (QM) and relativity (ER). Physics that incorporates elements of either QM or ER (or both) is said to be modern physics. It is in this latter sense that the term is generally used.[1]
Modern physics is often encountered when dealing with extreme conditions. Quantum mechanical effects tend to appear when dealing with "lows" (low temperatures, small distances), while relativistic effects tend to appear when dealing with "highs" (high velocities, large distances), the "middles" being classical behavior. For example, when analyzing the behavior of a gas at room temperature, most phenomena will involve the (classical) Maxwell–Boltzmann distribution. However near absolute zero, the Maxwell–Boltzmann distribution fails to account for the observed behavior of the gas, and the (modern) Fermi–Dirac or Bose–Einstein distributions have to be used instead.
Very often, it is possible to find – or "retrieve" – the classical behavior from the modern description by analyzing the modern description at low speeds and large distances (by taking a limit, or by making an approximation). When doing so, the result is called the classical limit.
^ abcF. K. Richtmyer; E. H. Kennard; T. Lauristen (1955). Introduction to Modern Physics (5th ed.). New York: McGraw-Hill. p. 1. LCCN 55006862.
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August 23, 2023
modern, physics, branch, physics, that, developed, early, 20th, century, onward, branches, greatly, influenced, early, 20th, century, physics, notable, branches, modern, physics, include, quantum, mechanics, special, relativity, general, relativity, classical,. Modern physics is a branch of physics that developed in the early 20th century and onward or branches greatly influenced by early 20th century physics Notable branches of modern physics include quantum mechanics special relativity and general relativity Classical physics is usually concerned with everyday conditions speeds are much lower than the speed of light sizes are much greater than that of atoms yet very small in astronomical terms Modern physics however is concerned with high velocities small distances and very large energies Classical physics is typically concerned with everyday conditions speeds are much lower than the speed of light sizes are much greater than that of atoms and energies are relatively small Modern physics however is concerned with more extreme conditions such as high velocities that are comparable to the speed of light special relativity small distances comparable to the atomic radius quantum mechanics and very high energies relativity In general quantum and relativistic effects are believed to exist across all scales although these effects may be very small at human scale While quantum mechanics is compatible with special relativity See Relativistic quantum mechanics one of the unsolved problems in physics is the unification of quantum mechanics and general relativity which the Standard Model of particle physics currently cannot account for Modern physics is an effort to understand the underlying processes of the interactions of matter using the tools of science amp engineering In a literal sense the term modern physics means up to date physics In this sense a significant portion of so called classical physics is modern 1 However since roughly 1890 new discoveries have caused significant paradigm shifts 1 especially the advent of quantum mechanics QM and relativity ER Physics that incorporates elements of either QM or ER or both is said to be modern physics It is in this latter sense that the term is generally used 1 Modern physics is often encountered when dealing with extreme conditions Quantum mechanical effects tend to appear when dealing with lows low temperatures small distances while relativistic effects tend to appear when dealing with highs high velocities large distances the middles being classical behavior For example when analyzing the behavior of a gas at room temperature most phenomena will involve the classical Maxwell Boltzmann distribution However near absolute zero the Maxwell Boltzmann distribution fails to account for the observed behavior of the gas and the modern Fermi Dirac or Bose Einstein distributions have to be used instead German physicists Albert Einstein 1879 1955 founder of the theory of relativity and Max Planck 1858 1947 founder of quantum theory Very often it is possible to find or retrieve the classical behavior from the modern description by analyzing the modern description at low speeds and large distances by taking a limit or by making an approximation When doing so the result is called the classical limit Classical physics Rayleigh Jeans law black line failed to explain black body radiation the so called ultraviolet catastrophe The quantum description Planck s law colored lines is said to be modern physics Contents 1 Hallmarks 2 See also 3 References 4 Notes 5 External linksHallmarks EditMain articles History of quantum mechanics and History of relativity These are generally considered to be the topics regarded as the core of the foundation of modern physics Atomic theory and the evolution of the atomic model in general Black body radiation Oil drop experiment Franck Hertz experiment Geiger Marsden experiment Rutherford s experiment Gravitational lensing Michelson Morley experiment Photoelectric effect Quantum thermodynamics Radioactive phenomena in general Perihelion precession of Mercury Stern Gerlach experiment Wave particle duality Solid state physicsSee also Edit Physics portalHistory of physics Classical physics Quantum mechanics Theory of relativity Quantum field theory Unified field theory Nuclear FissionReferences EditA Beiser 2003 Concepts of Modern Physics 6th ed McGraw Hill ISBN 978 0 07 123460 3 P Tipler R Llewellyn 2002 Modern Physics 4th ed W H Freeman ISBN 978 0 7167 4345 3 Notes Edit a b c F K Richtmyer E H Kennard T Lauristen 1955 Introduction to Modern Physics 5th ed New York McGraw Hill p 1 LCCN 55006862 External links Edit Retrieved from https en wikipedia org w index php title Modern physics amp oldid 1169180719, wikipedia, wiki, book, books, library,
