| The laws list: A |
The laws list A
aberration to Avogadro's hypothesis.
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A.
- aberration
-
- The apparent change in position of a light-emitting
object due to
the constancy of the speed of light and the motion of the observer
relative to the emitter. The effect is nonrelativistic; that is, special
relativity is not required to derive it: all that is needed is Newtonian
mechanics and the assumption of the constancy of the speed of light. The
effect is observable in the apparent change of position of stars due to
Earth's relative motion, and is responsible for the "tunnel vision" effect
of travelling at relativistic speeds.
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- ampere; A (after A.M. Ampere, 1775-1836)
-
- The fundamental
SI unit of
electric current, defined as the current that, when going through two
infinitely-long parallel conductors of negligible cross-section and placed 1
m apart
in vacuum, results in a force between the two conductors of 2 x 10-7
N/m.
-
- Ampere's law (A.M. Ampere)
-
- The line integral of the magnetic flux around a
closed curve is proportional to the algebraic sum of electric currents
flowing through that closed curve; or, in differential form,
curl B = J.
This was later
modified to add a second term when it was incorporated into
Maxwell's equations.
-
- anthropic principle
-
-
- weak anthropic
principle
-
- The conditions necessary for the development of intelligent life
will be met only in certain regions that are limited in space and time.
That is, the region of the Universe in which we live is not necessarily
representative of a purely random set of initial conditions; only those
favorable to intelligent life would actually develop creatures who
wonder what the initial conditions of the Universe were, and this
process can only happen at certain times through the evolution of any
given universe.
- strong anthropic
principle
-
- A more forceful argument than the
weak principle: It implies that if the laws of the Universe were not
conducive to the development of intelligent creatures to ask about the
initial conditions of the Universe, intelligent life would never have
evolved to ask the question in the first place. In other words, the laws
of the Universe are the way they are because if they weren't, no
intelligent beings would be able to consider the laws of the Universe at
all.
-
-
- Arago spot (D.F.J. Arago)
-
- A bright spot that appears in the shadow of a
uniform disc being backlit by monochromatic light emanating from a point
source.
-
- Archimedes' principle
-
- A body that is submerged in a fluid is
buoyed up by a force equal in magnitude to the weight of the fluid that is
displaced, and directed upward along a line through the center of gravity of
the displaced fluid.
-
- Atwood's machine
-
- A weight-and-pulley system devised to measure
the acceleration due to gravity at Earth's surface by measuring the net
acceleration of a set of weights of known mass around a frictionless pulley.
-
- Avogadro constant; L; NA
(Count A. Avogadro; 1811)
-
- The number of items in a sample of a
substance which is equal to the number of atoms or molecules in a sample of
an ideal gas which is at standard temperature and pressure. It is equal to
about 6.022 52 x 1023
mol-1.
-
- Avogadro's hypothesis (Count A.
Avogadro; 1811)
-
- Equal volumes of all gases at the same
temperature and pressure contain equal numbers of molecules. It is, in fact,
only true for ideal gases.
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