Quantum mechanics (QM; also known as quantum physics or quantum theory) including quantum field theory, is a fundamental branch of physics concerned with processes involving, for example, atoms and photons. In such processes, said to be quantized, the action has been observed to be only in integer multiples of the Planck constant, a physical quantity that is exceeding, indeed perhaps ultimately, small. This is utterly inexplicable in classical physics.
Topical Notes, Topical Notes, Problems, Presentations, Quiz, Test, Investigations, and Videos |
Atoms, Atomic mass, Mass number, and Isotopes |
Atomic Energy Levels |
Absorption and Emission Spectra |
Photoelectric effect, DeBroglie wavelength |
Models of Light: wave and particle |
Wave-function graphs |
Mass-Energy Equivalence |
Radioactive decay; alpha, beta and gamma decay |
Half life |
Nuclear Fission and Fusion |
Test your Understanding: Chapter 7 MCQ Quiz 1 Here Take Chapter 7 ReQuiz MCQ Quiz 2 Here |
Quantum mechanics gradually arose from Max Planck’s solution in 1900 to the black-body radiation problem (reported 1859) and Albert Einstein’s 1905 paper which offered a quantum-based theory to explain the photoelectric effect (reported 1887). The early quantum theory was significantly reformulated in the mid-1920s.
The mathematical formulations of quantum mechanics are abstract. A mathematical function, the wave function, provides information about the probability amplitude of position, momentum, and other physical properties of a particle.
Important applications of the quantum mechanical theory include superconducting magnets, LEDs and the laser, the transistor and semiconductors such as the microprocessor, medical and research imaging such as MRI and electron microscopy, and explanations for many biological and physical phenomena.