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Glossary F

Field effect transistor (FET)
A type of transistor commonly used for amplifying weak-signal.
The current flows down the channel between the source (source of
electrons) and the drain. The amount of current that flows is regulated
by the “Gate”, a small change in the voltage at the gate
can increase the current flow in the channel dramatically.
Fissile material
Isotopes which can undergo nuclear fission. Example of fissile
materials are Uranium-233, uranium-235, plutonium-239, plutonium-241.
Fission
Is a nuclear process in which a heavier unstable nucleus divides or splits
into two or more lighter nuclei, with the release of substantial amounts of energy.
When a free neutron of the proper energy is captured by the nucleus of a fissionable
atom, the resulting unstable nucleus will split producing two or more fission products
(atomic nuclei of different elements formed from the protons and neutrons originally
comprising the nucleus before its fission), two or three free neutrons and a tremendous
amount of energy.
Flux
The rate of flow of mass or energy per unit area in a certain direction.
This means the amount of energy that is flowing out from a source e.g. as a
blub gives off energy its flux changes depending on how far from the source you are
Flux density
The amount of flux per unit of cross-sectional area. The derived SI unit for
magnetic flux density is the Tesla.
Foucault pendulum
Is a tall pendulum free to oscillate in any vertical plane and
capable of running for hours. It is used to demonstrate Coriolis
force and the rotation of the earth. It is named after the inventor,
Léon Foucault. A Foucault pendulum at the equator does not
rotate. A pendulum at the pole rotates once a day. A pendulum
anywhere on the earth rotates with a speed proportional to the
sine of its latitude; thus one at 45° rotates once every 1.4 days
and one at 30° every 2 days. [more]
Fusion
Is a process where two small nuclei join together to form a larger
nucleus. Nuclear fusion is the energy source that causes stars to shine,
and is one of the processes in the hydrogen bomb.
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