- Focus on Physics

Glossary S

Schimidt Telescope
Light passes through a thin correcting
plate, is reflected by a large short-focus spherical mirror, and
focused on a curved photographic plate. In this kind of telescope,
corrects aberration, croma and astigmatism.
Named after Bernhard Schmidt.
Schrodinger’s Cat
Is a thought experiment that attempts
to illustrate the incompleteness of the theory of quantum mechanics
when going from subatomic to macroscopic systems. A cat is placed
in a sealed box. Attached to the box is an apparatus containing
a radioactive nucleus and a canister of poison gas. When the nucleus
decays, it emits a particle that triggers the apparatus, which
opens the canister and kills the cat. If the box is not open then
that cat could be alive or dead, we don’t know. But if we open
the box then we will know the state of the cat [Interactive Schrodinger’s Cat]
Seebeck Effect (Peltier Effect)
A when an current is passed through two
dissimilar conductors (n-type and p-type) that are connected to
each other at two junctions (Peltier junctions). The current drives
a transfer of heat from one junction to the other. Or Vice Versa
a temperature difference causes a current to flow between them.
Are materials with electrical conductivities
that are intermediate between those of conductors and insulators.
Semiconductors are useful for electronic purposes because they
can carry an electric current by electron propagation or hole
propagation, and because this current is generally uni-directional
and the amount of current may be influenced by an external agent
(see diode, transistor, amplifier etc.). [more]
Simple harmonic motion
Is the motion of a particle about a fixed
point such thats its acceleration is proportional to its displacement
from the fixed point. The acceleration is directed toward the
point. An example of this in terms of a mass on a spring or a
Solar Wind
A stream of particles (mostly high-energy protons ~ 500 Kev)
that is continually ejected from the surface of the Sun.
The composition of this plasma is identical to the Sun’s
corona, 73% hydrogen and 25% helium with the remainder
as trace impurities, and is ionized. Near Earth, the velocity of
the solar wind varies from 200km/s-889km/s. The average is 450
km/s. Approximately 3000 tons of material is lost from the Sun
every hour as solar wind. [more]
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