OSHA Laser Safety | Practice Test, Exam Questions & Verified Answers
Diffuse Reflection Takes place when different parts of a beam incident on a surface are reflected over
a wide range of angles in accordance with Lambert's Law. The intensity will fall off
as the inverse of the square of the distance away from the surface and also obey a
Cosine Law of reflection.
pumping system uses photons from another source as a xenon gas flash tube (optical pumping) to
transfer energy to the media, electrical discharge within the pure gas or gas mixture
media (collision pumping)
laser medium can be a solid (state), gas, dye (in liquid), or semiconductor. Lasers are commonly
designated by the type of lasing material employed.
Solid state lasers have lasing material distributed in a solid matrix, e.g., the ruby or
neodymium-YAG (yttrium aluminum garnet) lasers. The neodymium-YAG laser
emits infrared light at 1.064 micrometers.
Gas lasers (helium and helium-neon, HeNe, are the most common gas lasers) have a
primary output of a visible red light. CO2 lasers emit energy in the far-infrared, 10.6
micrometers, and are used for cutting hard materials.
Excimer lasers (the name is derived from the terms excited and dimers) use reactive gases
such as chlorine and fluorine mixed with inert gases such as argon, krypton, or
xenon. When electrically stimulated, a pseudomolecule or dimer is produced and
when lased, produces light in the ultraviolet range.
Dye lasers use complex organic dyes like rhodamine 6G in liquid solution or suspension as
lasing media. They are tunable over a broad range of wavelengths.
Semiconductor lasers, sometimes called diode lasers, are not solid-state lasers. These electronic
devices are generally very small and use low power. They may be built into larger
arrays, e.g., the writing source in some laser printers or compact disk players.
Absorb To transform radiant energy into a different form, with a resultant rise in
temperature.
Absorption Transformation of radiant energy to a different form of energy by the interaction of
matter, depending on temperature and wavelength.
Accessible Emission Level The magnitude of accessible laser (or collateral) radiation of a specific wavelength
or emission duration at a particular point as measured by appropriate methods and
devices. Also means radiation to which human access is possible in accordance
with the definitions of the laser's hazard classification.
Accessible Emission Limit (AEL) The maximum accessible emission level permitted within a particular class. In ANSI
Z 136.1, AEL is determined as the product of accessible emission Maximum
Permissible Exposure limit (MPE) and the area of the limiting aperture (7 mm for
visible and near-infrared lasers).
Aperture An opening through which radiation can pass.
Argon A gas used as a laser medium. It emits blue-green light primarily at 448 and 515
nm.
Stuvia 2026-2027
, OSHA Laser Safety | Practice Test, Exam Questions & Verified Answers
Attenuation The decrease in energy (or power) as a beam passes through an absorbing or
scattering medium.
Aversion Response Movement of the eyelid or the head to avoid an exposure to a noxious stimulant,
bright light. It can occur within 0.25 seconds, and it includes the blink reflex time.
Beam A collection of rays that may be parallel, convergent, or divergent.
Beam Diameter The distance between diametrically opposed points in the cross section of a circular
beam where the intensity is reduced by a factor of e-1 (0.368) of the peak level (for
safety standards). The value is normally chosen at e-2 (0.135) of the peak level for
manufacturing specifications.
Beam Divergence Angle of beam spread measured in radians or milliradians (1 milliradian = 3.4
minutes of arc or approximately 1 mil). For small angles where the cord is
approximately equal to the arc, the beam divergence can be closely approximated
by the ratio of the cord length (beam diameter) divided by the distance (range) from
the laser aperture.
Blink Reflex The visual sensation of the luminous intensity of a light source. The brightness of a
laser beam is most closely associated with the radio-metric concept of radiance.
Carbon Dioxide Molecule used as a laser medium. Emits far energy at 10,600 nm (10.6 µm).
Closed Installation Any location where lasers are used which will be closed to unprotected personnel
during laser operation.
CO2 Laser A widely used laser in which the primary lasing medium is carbon dioxide gas. The
output wavelength is 10.6 µm (10600 nm) in the far infrared spectrum. It can be
operated in either CW or pulsed.
Coherence A term describing light as waves which are in phase in both time and space.
Collimated Light Light rays that are parallel. Collimated light is emitted by many lasers. Diverging
light may be collimated by a lens or other device.
Collimation Ability of the laser beam to not spread significantly (low divergence) with distance.
Continuous Mode The duration of laser exposure is controlled by the user (by foot or hand switch).
Continuous Wave (CW) Constant, steady-state delivery of laser power.
Stuvia 2026-2027
Diffuse Reflection Takes place when different parts of a beam incident on a surface are reflected over
a wide range of angles in accordance with Lambert's Law. The intensity will fall off
as the inverse of the square of the distance away from the surface and also obey a
Cosine Law of reflection.
pumping system uses photons from another source as a xenon gas flash tube (optical pumping) to
transfer energy to the media, electrical discharge within the pure gas or gas mixture
media (collision pumping)
laser medium can be a solid (state), gas, dye (in liquid), or semiconductor. Lasers are commonly
designated by the type of lasing material employed.
Solid state lasers have lasing material distributed in a solid matrix, e.g., the ruby or
neodymium-YAG (yttrium aluminum garnet) lasers. The neodymium-YAG laser
emits infrared light at 1.064 micrometers.
Gas lasers (helium and helium-neon, HeNe, are the most common gas lasers) have a
primary output of a visible red light. CO2 lasers emit energy in the far-infrared, 10.6
micrometers, and are used for cutting hard materials.
Excimer lasers (the name is derived from the terms excited and dimers) use reactive gases
such as chlorine and fluorine mixed with inert gases such as argon, krypton, or
xenon. When electrically stimulated, a pseudomolecule or dimer is produced and
when lased, produces light in the ultraviolet range.
Dye lasers use complex organic dyes like rhodamine 6G in liquid solution or suspension as
lasing media. They are tunable over a broad range of wavelengths.
Semiconductor lasers, sometimes called diode lasers, are not solid-state lasers. These electronic
devices are generally very small and use low power. They may be built into larger
arrays, e.g., the writing source in some laser printers or compact disk players.
Absorb To transform radiant energy into a different form, with a resultant rise in
temperature.
Absorption Transformation of radiant energy to a different form of energy by the interaction of
matter, depending on temperature and wavelength.
Accessible Emission Level The magnitude of accessible laser (or collateral) radiation of a specific wavelength
or emission duration at a particular point as measured by appropriate methods and
devices. Also means radiation to which human access is possible in accordance
with the definitions of the laser's hazard classification.
Accessible Emission Limit (AEL) The maximum accessible emission level permitted within a particular class. In ANSI
Z 136.1, AEL is determined as the product of accessible emission Maximum
Permissible Exposure limit (MPE) and the area of the limiting aperture (7 mm for
visible and near-infrared lasers).
Aperture An opening through which radiation can pass.
Argon A gas used as a laser medium. It emits blue-green light primarily at 448 and 515
nm.
Stuvia 2026-2027
, OSHA Laser Safety | Practice Test, Exam Questions & Verified Answers
Attenuation The decrease in energy (or power) as a beam passes through an absorbing or
scattering medium.
Aversion Response Movement of the eyelid or the head to avoid an exposure to a noxious stimulant,
bright light. It can occur within 0.25 seconds, and it includes the blink reflex time.
Beam A collection of rays that may be parallel, convergent, or divergent.
Beam Diameter The distance between diametrically opposed points in the cross section of a circular
beam where the intensity is reduced by a factor of e-1 (0.368) of the peak level (for
safety standards). The value is normally chosen at e-2 (0.135) of the peak level for
manufacturing specifications.
Beam Divergence Angle of beam spread measured in radians or milliradians (1 milliradian = 3.4
minutes of arc or approximately 1 mil). For small angles where the cord is
approximately equal to the arc, the beam divergence can be closely approximated
by the ratio of the cord length (beam diameter) divided by the distance (range) from
the laser aperture.
Blink Reflex The visual sensation of the luminous intensity of a light source. The brightness of a
laser beam is most closely associated with the radio-metric concept of radiance.
Carbon Dioxide Molecule used as a laser medium. Emits far energy at 10,600 nm (10.6 µm).
Closed Installation Any location where lasers are used which will be closed to unprotected personnel
during laser operation.
CO2 Laser A widely used laser in which the primary lasing medium is carbon dioxide gas. The
output wavelength is 10.6 µm (10600 nm) in the far infrared spectrum. It can be
operated in either CW or pulsed.
Coherence A term describing light as waves which are in phase in both time and space.
Collimated Light Light rays that are parallel. Collimated light is emitted by many lasers. Diverging
light may be collimated by a lens or other device.
Collimation Ability of the laser beam to not spread significantly (low divergence) with distance.
Continuous Mode The duration of laser exposure is controlled by the user (by foot or hand switch).
Continuous Wave (CW) Constant, steady-state delivery of laser power.
Stuvia 2026-2027
