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

**Enthalpy**

It is heat function at constant pressure.
Mathematically expression is H=U+PV; ‘U’ is internal energy; ‘P’ is pressure
and ‘V’ is volume.

**Entropy
Maximum Principle**

For an isolated
system in state of equilibrium, the entropy attains maximum value and remains
constant.

**Entropy**

The
thermal property which remains constant during adiabatic process is called
entropy.

(or)

Measure of randomness or disorderliness of
molecules.

(or)

Index of unavailable energy of a system.

**Epicenter**

The point on the
surface directly above the “focus” is called Epicenter.

**Epitaxial
Growth**

The technique of
growing an oriented single crystal layer on a substrate wafer is called
epitaxial growth. The substrate crystal may be a wafer of same material as the
grown layer or a different material with similar lattice structure. The methods
which are adopted for this growth are i) Chemical vapor deposition. ii) Liquid
phase epitaxy iii) Molecular beam epitaxy

**Equal
Apriori Probability**

A
fundamental postulate of statistical mechanics is that a macroscopic system in
equilibrium is equally likely to be in any of its accessible microscopic states
satisfying macroscopic conditions of system.

(or)

The
probability of finding the phase point for given system in any region of phase
space is identical with that for any other region of equal extension or
volume.

**Equation
**

A mathematical
statement or formula which shows the equality of two expressions.

**Equation
of Continuity**

For any
incompressible & non-viscous fluid flowing steadily, the product of its
velocity and area of crossection at all points during its flow through a tube
remain constant. Velocity of fluid is
inversely proportional to area of crossection.

**Equation
of Motion of Rigid Body**

Relationship
between torque applied to rigid body and angular acceleration of body is known
as equation of motion of rigid body.

**Equation
of State **

An equation of state is a relation between
state variables. It is a thermodynamic equation which describes the state of
matter under a given set of physical conditions, typically relating energy,
temperature, volume, and pressure. Equations of state are most commonly used to
describe properties of fluids, such as liquids, gases and plasma though
equations of state may also be applied to solids.

**Equilibrium
of a Rigid Body**

If
a rigid body is subjected to number of forces acting on it and has neither
translatory nor rotatory motion, then it is said to be in equilibrium.
Following conditions are satisfied in such a case:

i)
The
algebraic sum of forces acting on it is zero (translational equilibrium)

ii)
The
algebraic sum of moments of all the forces about any point is zero.(rotational
equilibrium)

**Equilibrium
(Phase)**

The state of
system where the phase characteristics remain constant over indefinite time
periods is called as equilibrium. At equilibrium the free energy is least.

**Equipartition of Energy **

The theorem of
equipartition of energy states that molecules in thermal equilibrium have same
energy associated with each independent degree of freedom of their motion.

**Equipotential
Surface**

Surface on which
every point is at same potential and the electric field is at right angles to
all these points.

**Erecting
Lens **

An eye piece
sometimes used in Kepler telescopes that consists of four lenses and provides
an erect image, which is more convenient for viewing terrestrial objects than
the inverted image provided by simpler eye pieces.

**Erecting
Prism **

It is a system of
prisms that converts the inverted image formed by most types of astronomical
telescopes to an erect image, also known as inverting prism.

**Erg**

It is unit of energy
in CGS system of units. It is amount of work done by a force of one dyne
exerted for a distance of one centimeter. 1erg=10^{-7} J.

**Ergodic
Hypothesis**

The time average
of some property of a system in equilibrium is same as instantaneous ensemble
average.

**Error**

The difference
between measured value and true value is called as error.

**Escape
Velocity**

It is the minimum velocity with which a body should be projected from the surface of the planet so as to escape its gravitational field.