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
Soldering
It is a method of using a filler metal for
joining two metals without heating them to melting points.
or
The American
welding society defines soldering as metal coalescence below 800oF.
Soldering is a process in which two adjoining metal surfaces are bonded by
means of wetting the metal surfaces completely with molten filler material.
Solenoid
A solenoid is a coil of insulated or enameled wire wound on a
rod-shaped form made of solid iron, solid steel, or powdered iron. Devices of
this kind can be used as electromagnets, as inductors in electronic circuits.
Solid
state physics
Branch of physics
which deals with study of formation of crystal structures, mechanical &
electrical properties of solids.
Solubility
limit
The maximum
concentration of solute that may be added without forming a new phase is called
as solubility limit.
Solute
The constituent present in relatively small
amounts is called solute.
Solution
It is a homogenous mixture of a single phase
containing one or more chemical species dispersed on a molecular scale.
Solvent
The constituent of solution present in largest
amount is called solvent.
SONAR
(Sound Navigation And Ranging)
It is a device
used to find depth of a sea or to locate the underwater objects like iceberg,
submarine, shoals of fish etc. it consists of two parts; a transmitter which
emits the ultrasound waves in all directions and a receiver which detects
reflected ultrasound wave.
Sonic
boom
Sound generated
by an object like plane travelling through air higher than speed of sound. If plane
is flying faster than sound, then the pressure waves are left behind. As they
spread outwards from the points at which they were formed along the flight
path, they become concentrated at the edge of a cone. This reaches right down
to ground, where we hear a sonic boom.
Sorption
The taking up and holding of one substance
by another. Sorption includes the processes of absorption and adsorption.
Sound
Distance per unit time.
Spallation
Spallation
is generally defined as fragmentation of a target into many smaller components
as a result of impact or stress. Consequently nuclear spallation is defined as
disintegration of a target nucleus. Spallation is defined as disintegration of
a target nucleus into many small residual components such as alpha particles
and nucleus upon bombardment with a suitable projectile such as light or heavy
ion beams or neutrons. Nuclear spallation also occurs naturally in earth’s
atmosphere as a result of exposure of nuclides to energetic cosmic rays such as
protons.
For
instance, 8O16 + n -----à 3α+ 2p+3n.
Spallation
can be used for production of radio nuclides and for generation of neutron
beams in spallation neutron generators.
Spark
Chamber
A spark chamber
is a construction of metal plates placed in a sealed box. A high voltage is
applied between the plates and since they are close to each other, it creates a
big electric field. The plates are placed in a sealed box which is filled with
gas. The basic idea of the detector is simple. The travelling
particle will ionize the gas between the plates. Using a triggering system, the
high voltage is applied to the plates immediately after the particle went
through the chamber. This produces sparks on the exact trajectory of the
particle. The triggering system is made of two
scintillators coupled with a photomultiplier tube, one on top of the chamber
and the other below it. Observations are made for coincidences between the two
scintillators. When a coincidence is observed, a pulse is sent to a spark gap.
It triggers a capacitor to discharge itself in the chamber. Then, the data
acquisition system plays its role.
Spatial
Coherence
Coherence between the waves from coherent
source travelling side by side at some separation is called spatial coherence.
Special
Theory of Relativity
It
is the theory proposed by Einstein. The postulates are as follows:
i)
the fundamental laws of physics have the same form in all inertial systems.
ii)
The velocity of light in vacuum is independent of the relative motion of source
and observer.
Specific
Activity
Radio activity
per unit mass of a radio nuclide.
Specific
Charge
The ratio of charge to mass of an elementary particle is called as specific charge.
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