When an X-ray photon collides with an atom, the atom may absorb the energy of the photon and boost an electron to a higher orbital level or if the photon is very energetic, it may knock an electron from the atom altogether, causing the atom to ionize.

When the energy source is a synchrotron or the X-rays are focused by an optic like a polycapillary, the X-ray beam can be very small and very intense.

When the physician is ready to record diagnostic views, which are saved and can be more carefully scrutinized later, he activates the equipment to apply a significantly higher X-ray dose, termed cine, in order to create better quality motion picture images, having sharper radiodensity contrast, typically at 30 frames per second.

When he could, he continued to think about the physics of his doctoral thesis, and he developed the dynamical theory of X-ray diffraction, which he was later to use in his Habilitationsschrift.

When UV light or X-ray is absorbed by matter, electrons are excited from core levels into unoccupied states, leaving empty core states.

When the neutron star passes nearby or through the Be circumstellar disk, it will capture material and temporarily become an X-ray pulsar.

When these high speed electrons struck the atoms of the anode, they created X-rays by one of two processes, either Bremsstrahlung or X-ray fluorescence.

When an electron from the inner shell of an atom is lost due to some sort of excitation, it is replaced with an electron from the outer shell ; the difference in energy is emitted as an X-ray photon which has a wavelength that is characteristic for the element ( there could be several of characteristic wavelengths per element ).

When computed tomography or, more specifically, cone beam computed tomography or CBCT ( 3D X-ray imaging ) is used preoperatively to accurately pinpoint vital structures including the inferior alveolar canal, the mental foramen, and the maxillary sinus, the chances of complications might be reduced as is chairtime and number of visits.

When using photons, it is placed after the beam has passed through the X-ray target.

When a single photon is sent through an interferometer, it passes through both paths, interfering with itself, as waves do, yet is detected by a photomultiplier or other sensitive detector only once.

When an electron in an excited molecule or atom descends to a lower energy level, it emits a photon of light equal to the energy difference.

When the emission of the photon is immediate, this phenomenon is called fluorescence, a type of photoluminescence.

When the emission of the photon is delayed, the phenomenon is called phosphorescence.

When the photon is emitted at a distance equal to the Schwarzschild radius, the redshift will be infinitely large.

When the photon is emitted at an infinitely large distance, there is no redshift.

When such an electron decays without external influence, emitting a photon, that is called " spontaneous emission ".

When an electron meets a hole, it falls into a lower energy level, and releases energy in the form of a photon.

When this happens due to the presence of the electromagnetic field from a photon, a photon is released in the same phase and direction as the " stimulating " photon, and is called stimulated emission.

When it was found in 1900 by Max Planck that the energy of waves could be described as consisting of small packets or " quanta ", Albert Einstein further developed this idea to show that an electromagnetic wave such as light could be described as a particle ( later called the photon ) with a discrete quantum of energy that was dependent on its frequency.

When sodium or its compounds are introduced into a flame, they turn it yellow, because the excited 3s electrons of sodium emit a photon when they fall from 3p to 3s ; the wavelength of this photon corresponds to the D line at 589. 3 nm.

When such an electron decays without external influence, emitting a photon, that is called " spontaneous emission ".

When an atom is probed by an external mechanism, such as a photon or a beam of electrons with energies in the range of 2 keV to 50 keV, a core state electron can be removed leaving behind a hole.

When these are absent, however, optical detection is said to be " photon noise limited " as only the shot noise ( also known as " quantum noise " or " photon noise " in this context ) remains.

When a photon of sufficient energy strikes the diode, it excites an electron, thereby creating a free electron ( and a positively charged electron hole ).

When two nanowires acting as photon waveguides cross each other the juncture acts as a quantum dot.

When an electron and a hole recombine, it is possible for a photon to be emitted.

When the molecule relaxes it emits a photon and it returns to a different rotational or vibrational state.

When driving rain or mist socked in one valley, Fogg would chandelle up and over to reverse course and try another one, ranging from the Ottauquechee up to Danville in search of safe passage through the mountain passes.

When one station is finished with a car, it passes it on to the next.

When the serving side loses a rally, the serve immediately passes to their opponent ( s ) ( this differs from the old system where sometimes the serve passes to the doubles partner for what is known as a " second serve ").

When a funeral procession passes by the two girls and Laura begins singing a hymn, Carmilla bursts out in rage and scolds Laura for singing a Christian song.

When a medical doctor passes the examinations which enable them to become a member of one or more of the Royal Surgical Colleges and become " MRCS ", it is customary for them to drop the " Doctor " prefix and take up " Miss ", " Mister ", or and so on.

* When the key is released, the jack falls back down under its own weight, and the plectrum passes back under the string.

' When you say such you do not mean that the stone itself is Caesar, but rather, the name and honor you ascribe to the statue passes over to the original, the archetype, Caesar himself.

When the blade of an ice skate passes over the ice, the ice undergoes two kinds of changes in its physical state and a change in temperature due to kinetic friction and the heat of melting.

When knitting, some knitters enclose their balls in jars to keep them clean and untangled with other yarns ; the free yarn passes through a small hole in the jar-lid.

When the number of particles in one excited state exceeds the number of particles in some lower-energy state, population inversion is achieved and the amount of stimulated emission due to light that passes through is larger than the amount of absorption.

When no voltage is applied to a TN liquid crystal cell, polarized light passes through the 90-degrees twisted LC layer.

When a player passes, they can no longer bid.

When a beam of white light passes from air into a material having an index of refraction that varies with frequency, a phenomenon known as dispersion occurs, in which different coloured components of the white light are refracted at different angles, i. e., they bend by different amounts at the interface, so that they become separated.

When Mr. Dashwood dies, his estate, Norland Park, passes directly to his only son John, the child of his first wife.

When light of the appropriate frequency passes through the inverted medium, the photons stimulate the excited atoms to emit additional photons of the same frequency, phase, and direction, resulting in an amplification of the input intensity.

When Louise goes below deck momentarily, a large, strange cloud on the horizon passes over the craft, leaving a reflective mist on Scott's bare skin.

When this occurs the wing deflects the airflow downwards, " turning " the air as it passes the wing.

When a current passes through the galvanometer coil, a second magnetic field B perpendicular to the coil is created, of strength:

When the PDU passes over the interface from the layer that constructed it to the layer that merely delivers it ( and therefore does not understand its internal structure ), it becomes a service data unit to that layer.

When a signal passes through a non-ideal, non-linear device, additional content is added at the harmonics of the original frequencies.

When the racing car passes the start / finish line the lap time and the racing position is shown on the score board.

When Forney ’ s sister passes away due to alcoholism and he does not appear to be at the funeral, Novalee finds him in a hotel and comforts him.

When Mercury passes in front of the Sun, it is a transit of Mercury, and when Venus passes in front of the Sun, it is a transit of Venus.