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
Angstrom
It is the unit of
length usually used to express sizes at atomic scale. It is equal to 10-10
meter.
Angular Acceleration
It is defined as the
rate of change of angular velocity.
Angular Aperture
Angular aperture
of an objective is largest angular extent of wave surface which it can
transmit.
Angular Displacement
When a particle
describes circular path, the angle described by the radius vector in a given
time interval is called angular displacement. Its direction is perpendicular to
plane of rotation along the axis.
Angular Momentum
It is the ability
of a body by virtue of which it imparts rotatory motion to other bodies.
Angular momentum is product of linear momentum and perpendicular distance of
direction of linear momentum from center of rotation.
Angular velocity
It is defined as
rate of change of angular displacement.
Anisotropy
It is the
phenomenon of exhibiting different values of a physical property in different
crystallographic directions.
Annealing
It is the process
of heat treatment of metal by which microstructure and consequently properties
of a material are altered. Annealing is generally heating of metal to specific
temperature, for certain duration and then allowed to cool slowly thus
softening by re-crystallizing. Cold worked metals usually undergo this for
relieving strain.
Anode Rays
Rays of
positively charged particles formed inside gas discharge tubes. These rays were
discovered by Goldstein in 1886.
Anode
It is the
electrode in an electrochemical cell that experiences oxidation, or gives up
electron.
Anodizing
It is an
electrochemical metal finishing process used for increasing thickness and
toughness of the naturally occurring protective oxides on surface of metals.
The process is called anodizing, as the part to be chemically treated forms the
anode electrode of electric circuit. The process increases non-corrosiveness
& non-conductivity.
Anomalous Dielectric Dispersion
The fall in
permittivity of a dielectric material with increasing frequency of external
electric field is a phenomenon called anomalous dielectric dispersion.
Anomalous Expansion of Water
When temperature
of water is raised from 0 oC, its volume decreases up to 4 oC
and above 4oC its volume increases. This is called anomalous
expansion. It is due to formation of more number of Hydrogen bonds.
Anomalous Zeeman Effect
When spectral
lines of an atom split into three or more unequally spaced lines in the presence
of magnetic field then the phenomenon is called as anomalous Zeeman effect.
This usually happens for the systems where net spin i.e. spin quantum number is
not zero.
Antenna
A type of
transducer that converts RF fields into alternating current or vice versa. A
receiving antenna intercepts RF energy and delivers oscillating electric
current to electronic equipment, and the transmitting antenna is fed with
electric current to generate RF field. They consist of metallic conductors,
electrically connected to transistor or receiver.
Anti Ferromagnetism
Phenomenon of
magnetic moment (spin moments) of neighboring atoms or ions aligned in exactly
opposite directions.
Anti Logarithm
If ‘y’ is result of logarithm of a given
number ‘x’ then ‘x’ is antilog of ‘y’.
Anti Matter
Matter which
comprises of antiparticles.
Anti Particle
Every fundamental
particle is presumed to have an antiparticle which has same mass but opposite
charge.
Anti-Node
Position of
particles on a wave which vibrate simple harmonically with maximum amplitude is
called anti node.
Antistokes Lines
The smaller
frequency lines in Raman spectra are called Anti-Stokes lines.
Aphelion
The point in the
orbit of planet, at which it is farthest from sun, is termed as Aphelion.
Aperture
Word attributed
to small opening in an optical system or arrangement or instrument, through
which light is made to pass for focusing it on to any plane.
