Experiența Franck și Hertz Franck and Hertz Experiment

Experimentul Franck-Hertz a fost un experiment fizic care a furnizat suport pentru modelul Bohr al atomului, un precursor al mecanicii cuantice. În 1914, fizicienii germani James Franck și Gustav Ludwig Hertz au încercat să probeze experimental nivelele energetice ale atomului.

Astăzi celebrul experiment Franck-Hertz a adus dovada experimentală a modelului atomului propus de Niels Bohr, cu electroni orbitând nucleul cu niveluri discrete specificate de energie. Franck și Hertz au primit Premiul Nobel pentru Fizică în 1925 pentru acest experiment.

Experimentul Franck-Hertz a confirmat modelul cuantizat al lui Bohr pentru atom, demonstrând că atomii pot să absoarbe sau să cedeze energie doar în anumite cuante.

Wikipedia

The Franck–Hertz experiment was the first electrical measurement to clearly show the quantum nature of atoms, and thus "transformed our understanding of the world". It was presented on April 24, 1914 to the German Physical Society in a paper by James Franck and Gustav Hertz. Franck and Hertz had designed a vacuum tube for studying energetic electrons that flew through a thin vapor of mercury atoms. They discovered that, when an electron collided with a mercury atom, it could lose only a specific quantity of its kinetic energy (7.8×10-19 joules or 4.9 electron volts).

These experimental results proved to be consistent with the Bohr model for atoms that had been proposed the previous year by Niels Bohr. The Bohr model was a precursor of quantum mechanics; its key feature was that an electron inside an atom occupies one of the atom's "quantum energy levels". Before a collision, an electron inside the mercury atom occupies its lowest energy level. After the collision, the electron occupies a higher level with 4.9 electron volts (eV) more energy. There were no intermediate levels or possibilities in Bohr's quantum model. This feature was revolutionary because it was inconsistent with the expectation that an electron could be bound to an atom's nucleus by any amount of energy, just as a planet can be bound to a star by any energy.

Wikipedia