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
 
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Identical particles:

Two particles can be said to be identical if no observable effects whatever can arise from interchanging them. More precisely, all observable quantities must remain unaltered if the position, momentum and other dynamic variables such as spin of first particle are interchanged with those of second particle.

Ionizing Radiation: 

Fast charged particles, which deliver their energy to matter directly, through many small Coulomb-force interactions along the particle referred to as “Directly ionizing radiation”. (or) X-rays or Gamma ray photons or neutrons (i.e. uncharged particles) which first transfer their energy to charged particles in the matter through which they pass in a relatively few large interactions. The resulting fast charged particles then in turn deliver the energy to the matter through Coulomb force interaction.    

Indirect band semiconductor:

The semi conductor in which an electron in  conduction band (minimum) cannot fall to valence bond maximum but must undergo change in momentum, which may be caused by traps in energy gap. Generally the energy difference is given up as heat to lattice.    

Isobars:

The atoms which have same mass number but different atomic numbers.

 

Isotope:

The atoms of an element, which have same atomic number but different mass numbers. Number of protons inside th nucleus and number of electrons outside the nucleus of such atoms is same but number of neutrons inside the nucleus is different.

Isotones:

The atoms whose nuclei have same number of neutrons and protons are called isotones.

Isomers:

Atoms having same atomic number and mass number but differ from one another in their nuclear energy states and exhibit differences in internal structure. These nuclei are distinguished by their different life times. Such nuclei are called isomers.

Interference of light:

The change in uniform distribution of light intensity in a medium due to superposition of two light waves of nearly equal amplitudes, but of same frequency traveling in same direction, is called interference of light.

Irreversible change:

The change which cannot be reversed or the change which on reverse process, magnitudes of ∆Q, ∆U & ∆W are not same as in direct process is called irreversible change.

Intensity of radiation:

The intensity of radiation at a point is equal to the radiant energy incident per second on unit area of a surface at that point when the surface is held normal to the incident radiation.

Impulse:

It is the change in momentum when a large force acts for a short time interval.

Inelastic collision:

Collision in which only momentum is conserved but not kinetic energy; the colliding bodies undergo deformation.

Inertial frame:

The frame with respect to which an un-accelerated body appears un-accelerated is inertial frame. In other words, frames which are at rest or in uniform translator motion relative to one another are inertial frames.

(or)

Frame in which Newton’s first law is true.

Inertial mass:

The inertial mass of a body may be defined as the ratio of the inertial force acting on the body to the acceleration acquired.

Ideal fluid:

Fluid is called as ideal fluid if it has zero viscosity, zero compressibility, flow should be irrotational and steady.

Invariant tensor:

The tensor which has the same component in all coordinate systems is said to be invariant tensors.

Ionic bonding:

Type of bonding formed between metallic and non-metallic elements. Atoms of metallic element easily give up their valence electrons to non-metallic atoms.

Interfacial defect:

Interfacial defects are boundaries that have two dimensions and normally separate regions of material that have different crystal structures and/or crystallographic orientations.

Impurity diffusion:

Process, where by atoms of one metal diffuse into another is termed as impurity diffusion.