A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
Paschen
Series
The spectrum of wavelengths formed due to
electronic transitions from higher energy states to third orbit of atom. The
spectrum falls in infrared region.
Passive
Component
A passive device is one that contributes no
power gain (amplification) to a circuit or system. It has no control action and
doesn’t require any input than a signal to perform its function. In other words,
they are components with no brains. Resistors, Capacitors, Inductors, etc fall
under this class of components.
Pauli’s
Exclusion Principle
The principle is
postulated by an Austrian physicist Wolfgang Pauli in 1925. Pauli’s exclusion
principle says that two similar particles cannot exist in same state, i.e. they
cannot have both position and velocity same
within the limits given by uncertainty principle. The exclusion principle is
crucial because it explains why matter particles do not collapse to a state of
light density under influence of forces produced by particles of spin-0, 1&
2. If matter particles have nearly same positions, they must have different
velocities, which mean that they will not stay in same position for long.
Peak
Inverse Voltage
It is maximum reverse voltage that a diode can
with stand without destroying the junction.
Peltier
Effect
When an electric
current is passed through a junction of two dissimilar conductors , heat is
either absorbed or released at the junction , depending on direction of current.
Penetration
Depth
It is the depth from surface of metal at
which magnetic field falls to 1/e of its original value.
Penning
Effect
Mechanism of adding small quantities of
other gas having lower ionization potential into main gas, to reduce overall
work function of gas composition is called Penning effect. If the main gas
atoms having meta-stable excited states collide with additive gas atoms, then
energy is transferred to additive gas by ionizing its atoms. In this fashion
more charge is produced per unit energy of incident energy.
Penumbra
(“from the Latin words Paene which means
“nearly” and Umbra means “shadow” ) is the region in which only a portion of
the light source is obscured by occluding body.
or
Penumbra
is the region where some or the entire light source is obscured.
Perihelion
It is the point in the orbit of a planet,
where it is nearest to the sun.
Perigee
The point in the
orbit of an object orbiting the earth, nearest to center of earth is called as
Perigee. At its perigee, the objects travels faster than at any point in the
orbit.
Periodic
Motion
Any motion that repeats itself at regular
intervals of time is known as periodic motion.
Periodic
Table
Table used to
classify all the elements according to electron configuration. The elements are
arranged in table with increasing atomic number in horizontal rows. The
arrangement is such that all elements arrayed in a column or group has similar
valence electron structures as well as chemical and physical properties. These
properties change gradually and symmetrically, moving horizontally across each
period.
Periscope
An arrangement of
number of optical instruments like mirrors, lenses that enable user to view
objects that are not in direct line of vision, such as one in a submarine for
looking above surface of water.
Permanent
Magnets
They are materials which retains property of
magnetism unless heated to a high temperature. They are made of hard steel or
special alloys.
Permanent
Set
If wire is loaded beyond elastic limit, it
will not regain its original length even after deforming force is removed. When
the external load is completely removed, length of wire increased permanently
called permanent set.
Permeance
The reciprocal of
reluctance is called as Permeance.
Permeation
Passage of a gas into, through, and out of
a solid barrier; having no holes large enough to permit more than a small
fraction of gas to pass through any hole, is known as permeation.
Permittivity
It is the characteristic of dielectric
material which determines that how much the electric field influences the
material.
Perpendicular
Axes Theorem
Sum of the
moments of inertia of a uniform plane lamina about any two perpendicular axes
in its plane is equal to the moment of inertia of it about an axis
perpendicular to its plane which passes through the point of intersection of
first two axes.
No comments:
Post a Comment