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Glossary G

Galvanometer
An instrument for measuring small currents.
When a current is passed through a coil in a magnetic field, the
coil experiences a turning force proportional to the current.
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Gamma Rays
Are an energetic form of electromagnetic
radiation produced by radioactivity or other nuclear or subatomic
processes such as electron-position annihilation. Gamma rays are
more penetrating than either alpha or beta radiation, but less
ionizing. They are a form of electromagnetic radiation. Gamma
rays are distinguished from X rays by their origin. Gamma rays
are produced by nuclear transitions while X-rays are produced
by energy transitions due to accelerating electrons. Because it
is possible for some electron transitions to be of higher energy
than nuclear transition, there is an overlap between low energy
gamma rays and high energy X-rays.
Gay-Lussac Law
Different gases expand in volume by the same amount with the same
change in temperature. Named after Joesph Gay-Lussac a French Chemist
but better known today as Charles’s Law after fellow countryman Jacque Charles.
Geiger Counter
A device used to detect ionizing radiation like alpha, beta or gamma rays.
Gergorian telescope
A reflecting telescope with a hole in the primary mirror (parabolic).
The light is reflected off the primary mirror and then hits a secondary
concave mirror that focused the light down to the viewer. Very similar
to a Cassegranian Telescope except that a the secondary mirror that
telescope is a convex mirror. Named after James Gergory.
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