Energy particle-like properties

There is a mind-blowing paradox at the heart of all discussions about light. Light is a form of energy that exhibits both wave-like and particle-like properties. In other words, a photon is simultaneously both a wave and a particle. We can never fully understand this paradox, but will merely say that extremely small particles exhibit a... 

The development of the quantum theory in the early twentieth century allowed predictions to be made relating to the properties and behaviour of matter and light. The electrons in matter have both wavelike and particle-like properties, and quantum theory shows that the energy of matter is quantised that is, only certain specific energies are allowed. 

According to the quantum theory, light is also quantised. The absorption or emission of light occurs by the transfer of energy as photons. These photons have both wavelike and particle-like properties and each photon has a specific energy, E, given by Planck s law ... 

In addition to its wavelike properties, light also exhibits particle-like properties, such as for the photoelectric effect. Thus light can act as if it were divided — or quantized — into discrete units, which we call photons. The light energy (Ex) carried by a photon is... 

Eqs (2.9) and (2.10) constitute quantitative realizations of the wave-partiele duality, each relating a particle-like property—energy or momentum—to a wavelike property—frequency or wavelength. 

Wave-particle duality means that matter has wavelike properties and energy has particle-like properties. These properties become observable only at the atomic scale. Because of wave-particle duality, we can never know the exact position and momentum of an electron simultaneously [uncertainty principle). 

For very tiny objects, such as electron, quantum mechanics is needed. Max Planck (1858-1947) is considered as the father of quantum mechanics. Salient point of quantum mechanics is that aU matters and energy exhibit both wave-like and particle-like properties. If the size of the object is large, its wavelength will be too small to be observed. Also, there is a famous uncertainty principle that states that as one makes more precise measurement of the position of an object, the uncertainty in its momentum increases. 

QUANTIZED ENERGY AND PHOTONS We recognize that electromagnetic radiation also has particle-like properties and can be described in terms of photons, particles of light. 

Electromagnetic radiation is a form of energy that travels through space at a constant speed of 3.0 X 10 m/s and can exhibit wavelike or particle-like properties. 

In his doctoral dissertation de Broglie postulated that particles such as the electron, proton, etc. should also possess wave-like properties in exact analogy with the particle-like properties exhibited by electromagnetic waves in the quantum theory of radiation. For motion in one dimension he postulated that the momentum of the particle p and its kinetic energy E were related to the wavevector k and angular frequency w of the guiding wave, I, by the relations... 

As you learned from the previous section, three quantum numbers—n, 1, and mi—describe the energy, size, shape, and spatial orientation of an orbital. A fourth quantum number describes a property of the electron that results from its particle-like nature. Experimental evidence suggests that electrons spin about their axes as they move throughout the volume of their atoms. Like a tiny top, an electron can spin in one of two directions, each direction generating a magnetic field. The spin quantum number (mj specifies the direction in which the electron is spinning. This quantum number has only two possible values or —... 

Planck s constant h) immutable number relating particle energy, a corpuscular property, to wavelength, a wave property, in quantum physics pulsar neutron star with a high magnetic field, emitting narrow beams of radiation, rather like a lighthouse... 

The conventional macroscopic Fourier conduction model violates this non-local feature of microscale heat transfer, and alternative approaches are necessary for analysis. The most suitable model to date is the concept of phonon. The thermal energy in a uniform solid material can be jntetpreied as the vibrations of a regular lattice of closely bound atoms inside. These atoms exhibit collective modes of sound waves (phonons) wliich transports energy at tlie speed of sound in a material. Following quantum mechanical principles, phonons exhibit paiticle-like properties of bosons with zero spin (wave-particle duality). Phonons play an important role in many of the physical properties of solids, such as the thermal and the electrical conductivities. In insulating solids, phonons are also (he primary mechanism by which heal conduction takes place. 

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