When ionizing radiation strikes a semiconductor, it may excite an electron out of its energy level and consequently leave a hole.

When enough energy is deposited in a droplet by ionizing radiation the superheated droplet undergoes a phase transition and becomes a gas bubble.

When ionizing radiation is emitted by or absorbed by an atom, it can liberate a particle ( usually an electron, but sometimes an entire nucleus ) from the atom.

When the voltage difference between the conductors exceeds the gap's breakdown voltage, a spark forms, ionizing the gas and drastically reducing its electrical resistance.

When ionizing radiation is used to treat cancer, the doctor will usually prescribe the radiotherapy treatment in units of gray.

When health risk from ionizing radiation is being discussed, the sievert would be used.

When a sufficiently high voltage is applied, a spark will bridge the gap, ionizing the gas and drastically reducing its electrical resistance.

When a continuum radiation source is used for AAS, it is necessary to use a high-resolution monochromator, as will be discussed later.

When a continuum radiation source is used for AAS measurement it is indispensable to work with a high-resolution monochromator.

When exposed to sunlight, artificial light, or infrared radiation ( even the heat of a hand nearby can be enough ), the vanes turn with no apparent motive power, the dark sides retreating from the radiation source and the light sides advancing.

When these crystals are exposed to radiation, the dysprosium atoms become excited and luminescent.

When any wire ( or other conducting object such as an antenna ) conducts alternating current, electromagnetic radiation is propagated at the same frequency as the electric current.

When EM radiation interacts with matter, its behavior changes qualitatively as its frequency changes.

When EM radiation at the frequences for which it is referred to as " radio waves " impinges upon a conductor, it couples to the conductor, travels along it, and induces an electric current on the surface of the conductor by moving the electrons of the conducting material in correlated bunches of charge.

When electromagnetic radiation is incident on matter, it causes the charged particles to oscillate and gain energy.

When matter ( ordinary material particles ) is changed into energy ( such as energy of motion, or into radiation ), the mass of the system does not change through the transformation process.

When the first scientific satellites were launched in the first half of 1958 — Explorers 1 and 3 by the US, Sputnik 3 by the Soviet Union — they observed an intense ( and unexpected ) radiation belt around Earth, held by its magnetic field.

When lifeforms take such giant leaps, they meet little to no competition and are able to exploit a plethora of available niches, following a pattern of adaptive radiation.

* When an < sup > 235 </ sup > U atom captures a neutron, it is converted to an excited state of < sup > 236 </ sup > U. About 81 % of the excited < sup > 236 </ sup > U nuclei undergo fission, but the remainder decay to the ground state of < sup > 236 </ sup > U by emitting gamma radiation.

When a star has lost enough material, its temperature increases and the ultraviolet radiation it emits can ionize the surrounding nebula that it has thrown off.

When the direct solar radiation is not blocked by clouds, it is experienced as sunshine, a combination of bright light and radiant heat.

When ultraviolet radiation is not absorbed by the atmosphere or other protective coating, it can cause damage to the skin known as sunburn or trigger an adaptive change in human skin pigmentation.

When a population inversion () is present, therefore, optical amplification of incident radiation will take place.

When wavelengths of electromagnetic radiation are quoted, the wavelength in vacuum usually is intended unless the wavelength is specifically identified as the wavelength in some other medium.

When ground down to sizes less than 10 micrometres, the grains are removed from the inner solar system by solar radiation pressure.

When heat radiates from the surface of the earth, it is released as long-wave radiation, which can move freely through gases composed of diatomic molecules ( such as the atmosphere's oxygen and nitrogen ), but is readily absorbed by triatomic molecules, such as carbon dioxide and water vapor.

When combined with measurements of the cosmic microwave background radiation these implied a value of, a result which has been supported and refined by more recent measurements.

When the density and temperature are high enough, deuterium fusion begins, and the outward pressure of the resultant radiation slows ( but does not stop ) the collapse.

When the rear radiation is absorbed or trapped in a box, the diaphragm becomes a monopole radiator.

When words can be used in a more fresh and primitive way so that they strike with the force of sights and sounds, when tones of sound and colors of paint and the carven shape all strike the sensibilities with an undeniable force of data in and of themselves, compelling the observer into an attitude of attention, all this imitates the way experience itself in its deepest character strikes upon the door of consciousness and clamors for entrance.

When the plague strikes, he finds himself trapped in a city with which he feels he has no connection.

When Young's career began, pitchers delivered the baseball underhand and fouls were not counted as strikes.

When the key is pressed, the tangent strikes the strings above, causing them to sound in a similar fashion to the hammering technique on a guitar.

When light strikes a material, most of the light is absorbed while a smaller amount of a particular frequency or wavelength is reflected.

When the hammer strikes, the head gets stopped by an opposite force coming from the target ; which is equal and opposite to the force applied by the head to the target.

When the colonial administration rejected the People's Assembly's recommendations, Nkrumah organized a " Positive Action " campaign on 01 January 1950, including civil disobedience, non-cooperation, boycotts, and strikes.

When a wave strikes a reflective surface, it changes direction, such that the angle made by the incident wave and line normal to the surface equals the angle made by the reflected wave and the same normal line.

When a returning reflection strikes another discontinuity, some of the signal rebounds in the original signal direction, creating multiple echo effects.

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 the second mallet strikes the bar the first mallet is removed.

When a hollow-point hunting bullet strikes a soft target, the pressure created in the pit forces the material ( usually lead ) around the inside edge to expand outwards, increasing the axial diameter of the projectile as it passes through.

When Perseus arrives in Larissa, he participates in some funeral games and accidentally strikes Acrisius on the head with a discus, killing him and fulfilling the prophecy.

When Hymir refuses to provide Thor with bait, Thor strikes the head off Hymir's largest ox to use as his bait.

When whites used economic retaliation local Blacks seeking school integration in 1956 after the US Supreme Court ruling declaring segregation in public schools to be unconstitutional, students came to their support with hunger strikes, boycotts, and mass marches.

When Perry took over in 1994, the Bosnian Serbs were besieging Sarajevo, the Bosnian capital, but the Serbs were forced to draw back in face of a UN ultimatum and warning of air strikes.

When a clavichord key is pressed, a small metal tangent strikes a string and remains in contact with it for as long as the key is held down.

When the fee goes up to two bars, Farwell strikes DeCruz with the gold bricks, killing him.

When the UV photon strikes a phosphor molecule, it momentarily raises the energy level of an outer orbit electron in the phosphor molecule, moving the electron from a stable to an unstable state ; the electron then sheds the excess energy as a photon at a lower energy level than UV light ; the lower energy photons are mostly in the infrared range but about 40 % are in the visible light range.

When a bowler bowls two strikes in succession, within a game, the bowler has scored a " double ".

When a bowler bowls three strikes in succession, within a game, the bowler has scored a " triple " ( also called a " turkey ").

When light strikes a charged photocathode plate, electrons are emitted through a vacuum tube that strike the microchannel plate that cause the image screen to illuminate with a picture in the same pattern as the light that strikes the photocathode, and is on a frequency that the human eye can see.