Cornell University. Liev B. Jared E. University of Winnipeg. Meghan M. McMaster University. Physics Bootcamp Lectures Wave Optics - Intro In physics, wave optics is…. Multiple Aperture Interference - Overview Interference is a phenomen….
Recommended Videos Problem 2. Problem 3. Problem 4. Problem 5. Problem 6. The wavelength of energy emitted by an object depends on only its temperature, not its surface or composition. Hence an electric stove burner or the filament of a space heater glows dull red or orange when heated, whereas the much hotter tungsten wire in an incandescent light bulb gives off a yellowish light. The intensity of radiation is a measure of the energy emitted per unit area.
One of the major assumptions of classical physics was that energy increased or decreased in a smooth, continuous manner. Thus energy could be gained or lost only in integral multiples of some smallest unit of energy, a quantum the smallest possible unit of energy. Energy can be gained or lost only in integral multiples of a quantum.. In addition to being a physicist, Planck was a gifted pianist, who at one time considered music as a career. During the s, Planck felt it was his duty to remain in Germany, despite his open opposition to the policies of the Nazi government.
Although quantization may seem to be an unfamiliar concept, we encounter it frequently. For example, US money is integral multiples of pennies. Similarly, musical instruments like a piano or a trumpet can produce only certain musical notes, such as C or F sharp. Because these instruments cannot produce a continuous range of frequencies, their frequencies are quantized.
Planck postulated that the energy of a particular quantum of radiant energy could be described Max Planck — by the equation. For our purposes, its value to four significant figures is generally sufficient:. As the frequency of electromagnetic radiation increases, the magnitude of the associated quantum of radiant energy increases.
As the temperature of an object increases, there is an increased probability of emitting radiation with higher frequencies, corresponding to higher-energy quanta. The Photoelectric Effect: When light was used to knock electrons out of solids, the results were completely different than expected from Maxwell's equations. The measurements were easy to explain for Einstein if light is made up of particles with the energies Plank postulated.
Atoms: After Rutherford found that the positive charge in atoms was concentrated in a very tiny nucleus, classical physics predicted that the atomic electrons orbiting the nucleus would radiate their energy away and spiral into the nucleus.
This clearly did not happen. The energy radiated by atoms also came out in quantized amounts in contradiction to the predictions of classical physics. The Bohr Atom postulated an angular momentum quantization rule, for , that gave the right result for hydrogen, but turned out to be wrong since the ground state of hydrogen has zero angular momentum.
The closer the electron is to the nucleus the stronger the nucleus pulls and so the larger the magnitude of the potential energy. Suppose you want to move the electron farther from the nucleus and keep it going at the same speed.
Then you have to give the electron energy. So at the same speed it has more energy farther from the nucleus. So the electron is losing energy as it moves toward the nucleus since its negative potential energy is larger closer to the nucleus. It gets rid of that energy by radiating. Its orbit just decays a lot slower than the orbit of an electron cuz electromagnetic forces are stronger.
A small fridge magnet can hold a pin up against the gravitational force of the whole Earth. But the explanation is a bit more compliated because gravity is a bit more complicated. Cuz electromagnetic forces are a lot stronger they die away faster so orbits have to be closer, and the orbits also decay faster cuz the attraction is stronger.
In classical physics and in QM if an electron is going to lose energy and move to a lower state in the atom it will emit light. A rock orbiting the Earth will emit gravitational waves instead of light if its orbit is decaying.
There is a gravitational field, which is similar to the electromagnetic field but with different equations of motion. Gravitational waves are waves in the gravitational field. Pingback: Why are atoms stable in quantum mechanics?
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Home Epistemology mind node. Posts Comments. Uncategorized epistemology moral philosophy political philosophy physics multiverse everett quantum mechanics scientism. Why are atoms stable in quantum mechanics? Why atoms are unstable in classical physics November 24, 24 Comments. Share this: Twitter Facebook.
Like this: Like Loading November 28, at am. The electric force is kinda like gravity but different in some respects. Elliot Temple says:. November 28, at pm.
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