Earth
One of the nine
planets revolving around sun and is third planet orbiting from sun. The
distance of orbit from sun is 149,600,000Km and has diameter of 12,756.3Kms. It
is the fifth largest of the planets. The Mass is about 5.97x1024 Kg
Echo
Repetition of
sound produced due to reflection by a distant extended surface like cliff,
hill, well, building etc., is called an echo. The effect of sound on human ear
remains 1/10th of second. If sound reflects back in a time less than
1/10th of second, no echo is heard.
Eddy
Current
When a metal body
is moved in a magnetic field in such a way that the magnetic flux through it
changes or is placed in a changing magnetic field, induced current circulates
throughout the body. They are called
eddy currents.
Edge
Dislocation
A linear
crystalline defect associated with the lattice distortion produced in the
vicinity of the end of an extra half plane of atoms within a crystal. The
burgers vector is perpendicular to the dislocation.
Effective
Mass of Electron
The mass of an
electron inside crystal appears, in general, different from free electron mass
and is referred to as effective mass. The effective mass can be greater or
lesser than electron mass.
Efficiency
of Engine
The ratio of
useful work obtained by the engine in one cycle to the heat absorbed from the
source is called efficiency of engine.
Effusion
Effusion is the
process in which individual molecules flow through a hole without collisions
between molecules. This occurs if diameter of the hole is considerably smaller
than the mean path of molecules. According to Graham’s law, rate at which gas
effuse is dependent on their molecular weight; gases with lower molecular
weight effuse more quickly.
Eigen
Function
It is wave
function for a given physical system which contains measurable information
about system.
Eigen
Value
The word is
derived from German word “Eigenwert” which means characteristic value. A scalar
associated with a given linear transformation of vector space and having the
property that there is some non zero vector which when multiplied by scalar is
equal to vector obtained by letting the transformation operate on the vector.
Einstein
Shift
In astrophysics, gravitational red shift or Einstein
shift is the process by which electromagnetic radiation originating from a source that is
in gravitational field is reduced in frequency,
or red shifted, when observed in a region of a weaker gravitational
field. This is a direct result of Gravitational time dilation - as one moves away from a source of
gravitational field, the rate at which time passes is increased relative to the
case when one is near the source. As frequency is inverse of time
(specifically, time required for completing one wave oscillation), frequency of
the electromagnetic radiation is reduced in an area of a higher gravitational
potential (i.e., equivalently, of lower gravitational field). There is a
corresponding reduction in energy when electromagnetic radiation is
red-shifted, as given by Planck's relation, due to the electromagnetic radiation
propagating in opposition to the gravitational gradient.
Einstein
Theory of Specific Heats
A theory of the specific heat capacity of solids put forward
by Albert Einstein in
1906, in which it was assumed that the specific heat capacity is a consequence
of the vibrations of the atoms of the lattice of the solid. Einstein assumed
that each atom has the same frequency. The theory leads to the correct
conclusion that the specific heat of solids tends to zero as the temperature
goes to absolute zero, but does not give a correct quantitative description of
the low temperature behavior of the specific heat capacity.
