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
Alternating Current
Current in which
charge periodically reverses and average value is zero. It usually implies a
sinusoidal variation of current and voltage.
Altitude
The height of an
object with reference to sea level or ground level is called as altitude.
Ammeter
Device used to
measure current. It is designed with a small resistance put in parallel to the
galvanometer. It is generally connected in series with in a circuit, in which
electric resistance is to be measured.
Amorphous
Materials that do
not crystallize, i.e. in which, long range atomic order is absent, are referred
to as amorphous.
Ampere
It is the
constant current which if maintained in two straight parallel conductors of
infinite length and of negligible cross-section and placed one meter apart in
vacuum, would produce between these conductors a force equal to 2 x 10-7
N/M of length.
Amperes Law
A
law of electromagnetism which expresses contribution of a current element of
length dl to the magnetic induction ‘B’ at a point near the current carrying
element. The law was derived by A M Ampere. Whenever an electric charge is in
motion, there is magnetic field associated with that motion. The flow of
charges through a conductor sets up magnetic field in the surrounding region.
Any current may be considered to be broken up into infitesimal elements of
length dl and each such element contributes to magnetic induction at
every point in neighborhood. The contribution dB of the element is found to
depend upon current I, the length dl of element, distance ‘r’ of point ‘p’ from current element,
and angle ‘Ѳ’ between
current element and line joining point ‘p’.
dB= (KldIsinѲ/r2); K = µo/4Π = 10-7
Weber/Ampere-meter
Amplifier
Device used for
increasing the strength of a weak signal.
Amplitude Modulation
The process of
changing the amplitude of high frequency carrier wave in accordance with
intensity of signal without changing frequency, is called amplitude modulation.
Amplitude
The maximum displacement
of a vibrating particle in simple harmonic motion is called as amplitude.
Analog
Analog is defined
as a mechanism in which data is represented by continuously variable physical
quantities.
Anelasticity
In some
engineering materials, there also exists time dependent elastic strain
component. That is elastic deformation will continue even after stress
application and upon load release, some finite time is required for complete
recovery. This time dependant elastic behavior is known as anelasticity.
Anemometer
The term is
derived from Greek word “anemos”, meaning wind. It is device used for measuring
speed of air flow in wind tunnels, and in other gas flow applications.
Angle
The amount of
space between two straight lines having a common end point usually measured in
degrees.
Angle of Incidence
Angle between
incidence ray and normal to the surface is called angle of incidence.
Angle of Minimum Deviation
When the angle of
incidence in a prism is increased, the value of angle of deviation first
decreases and then increases. The minimum value of deviation is called the
angle of deviation.
Angle of Reflection
It is the angle
between reflected ray and normal to the surface, from which light is reflected.
Angle of Refraction
It is the angle
between refracted ray and the surface from which light is refracted.
