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
Graham’s
Law
At constant pressure and temperature, the
rate of diffusion of a given mass of gas is inversely proportional to the
square root of its density.
Grain
Boundary
It is defined as boundary separating two small grains or crystals
having different crystallographic orientations in poly-crystalline materials.
Grain
Many crystalline
solids are composed of collection of many small crystals called grains.
Gram
Atomic Weight
Quantity of an
element whose weight in grams is equal to atomic weight of element is called
Gram Atomic Weight.
Gram
Molecular Volume
The
volume occupied by a mole of any gas is called gram molecular volume.
At
0oC and 76 cm Hg pressure, the gram molecular volume of any gas is
22.4 liters.
Gram
Molecular Weight
Relative
molecular mass of a substance expressed in grams with reference to the atomic
weight of Hydrogen.
Gramophone
It is the first device for recording and
replaying.
Grand
Canonical Ensemble
It is collection
of large number of essentially independent systems having same temperature,
volume and chemical potential. The
individual systems of a grand canonical ensemble are separated by rigid
permeable and conducting walls.
Grand
Unified Theory
Physics theory
that can combine 3 of 4 fundamental forces into one single equation. The four
forces are strong nuclear force, the weak nuclear force, electromagnetic force
and gravitational force. Combining of 3 interactions strong nuclear, weak
nuclear and electromagnetic force is called unified theory.
Gravitational
Constant
The gravitational
force between two unit masses separated by unit distance is called universal
gravitational constant. The value of “G” is 6.67*10-11 Nm2 Kg-2.
Gravitational
Force
It is a long
range and central force, which is attractive in nature and acts between any two
masses in the universe.
Gravitational
Intensity
Gravitational
force of attraction exerted by a body on unit mass is called gravitational
intensity.
Gravitational
Mass
The ratio of gravitational force acting on
a body to the acceleration due to gravity is called as gravitational mass.
Gravitational
Potential
Gravitational
potential at a point in gravitational field is amount of work done in bringing
a unit mass from infinity to that point.
Graviton
Hypothetical
particle assumed to be responsible for gravitational field just as photons for
electromagnetic field. They are categorized as mass less Boson having spin-2
and mass zero.
Gravity
Phenomenon of
attraction between two bodies due to existence of gravitational force acting
along the line joining their centers.
Gray
It is the SI unit
for Radiation Absorbed Dose (RAD) which is equal to absorption of 1 Joule per
Kg of material.
Great
Circle
A great circle of
sphere is intersection of sphere and plane which passes through center point of
sphere. It is the largest possible circle that can be drawn around a sphere. All
spheres have great circles. Great circle has same circumference and the center
point same as its sphere. The geometry of spheres is useful for mapping the
earth and other planets. All the meridians on earth are great circles.
Green
House Effect
In green house,
plants etc are enclosed in glass structure. The glass allows short wavelength
radiation to enter. This radiation is absorbed by plants matter. It is
subsequently radiated in the form of longer wavelength heat radiation, infrared
rays. But they are not allowed to escape from glass. The heat radiation is
trapped in green house keeping it warm. Similar effect takes place in
atmosphere and is called green house effect.
Green’s
Theorem
This theorem is
an applicable of fundamental theorem of calculus to integrating a certain
combinations of derivatives over a plane. Suppose ‘R’ is a differentiable
function. A double integral of certain type of function over a plane region ‘R’
can be expressed as line integral (of some function) along the boundary curve
of R. This is called Green’s theorem.
Gregorian Telescope
Telescope designed by Scottish mathematician and astronomer James Gregory in 17th century. It is a reflecting telescope that has a parabolic primary mirror and a hyperbolic secondary mirror, light is brought to focus through an aperture in center of primary mirror.
Gross
Error
The errors due to
faulty adjustment or improper usage of an instrument are called gross errors.
Ground
Entity in
electric or electronic circuits.
Ground
State
When all
electrons occupy lowest possible energy state then atom is said to be in ground
state.
Group
Velocity
When a number of
progressive waves of slightly different wavelengths in a group superpose each
other, the velocity with which the wave packet or the point of reinforcement
advances in medium is called group velocity.
Guard
Ring
Extra electrode
used in gas filled radiation detectors to minimize surface electric leakage
currents of insulators.
Gyration
Simultaneous
precession, nutation & rotation of body is called gyration of the body.
Gyro
Compass
A gyrocompass is
a motorized gyroscope, used widely on ships employing an electrically powered
fast spinning gyroscope wheel, whose angular momentum interacts with force
produced by the earth’s rotation to maintain a north – south orientation of
gyroscopic spin axis there by providing as stable directional reference.
Gyroscope
If the fixed
point, about which a symmetrical body is spinning about its axis, coincides
with center of gravity of body, then it is known as gyroscope. The device
consists of rotation, precession and nutation.
