Showing posts with label matter. Show all posts
Showing posts with label matter. Show all posts


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Quantum of a spin wave.


A quasi particle introduced to describe small departures from complete ordering of electron spins in ferro, ferri, and antiferro- magnetic substances.  

Majarona Forces

A nuclear force in which there is exchange of position coordinates only but not spin coordinates.


Device used to measure pressure in terms of difference in height of two mercury columns, one open to atmosphere and other connected to source of unknown pressure.

Marginal Rays

The rays of light incident from the principle axis are called marginal rays.


It is fourth planet from sun in our solar system named after Roman god of war; which has period of revolution about sun of 687 days at a mean distance of 227.9 million km and a mean diameter of approximately 6,794kms.


It is a meta-stable iron phase super saturated in Carbon that is the product of diffusion less transformation from Austenitic. 


It is acronym for Microwave Amplification by Stimulated Emission of radiation. First MASER was built in 1951 by Charles. H. Townes. It is a device for coherent amplification or generation of electromagnetic waves by use of excitation energy in resonant atomic or molecular systems. The device uses an unstable ensemble of atoms or molecules that may be stimulated by an electromagnetic wave to radiate energy at same frequency and phase as simulating wave, thus providing coherent amplification.  

Mass Defect

The measured mass or actual mass of atom is less than sum of masses of constituent nucleons. The difference is referred to as    mass defect.

Mass Number

It is the number which represents the total sum of nucleons for a particular atom. It is denoted as superscript to an element.

Mass Spectrometer

Mass spectroscopy is a methodology that is extensively used to determine properties of charged particles. The basic principle of this technique is to dissociate the sample into smaller fragments and then let them pass through a high magnetic field. The charged particles get deflected in the magnetic field with the degree of deflection proportional to their mass to charge ratio (m/e). These deflected particles are then collected by a position sensitive detector, such as a micro channel PMT.


Mass is an attribute and not a physical thing. Mass is the attribute “inertia” of a physical object or of whatever is contained in a specific region of space.

Materialistic Wave

Louis de Broglie postulated that a wave has to be associated with each moving material particle called as matter wave. The wavelength of this wave is determined by momentum of particle. The waves are not perceptible for macroscopic bodies but for microscopic bodies.

Material Science/Engineering

The discipline of materials science involves the investigating the relationships that exist between the structures and properties of materials. In contrast, Materials Engineering is on the basis of these structure-property correlations, designing or engineering the structure of a material to produce a predetermined set of properties.

Matheissan’s Rule

According to this rule, electrical resistivity of metals is sum of resistivity due to impurities and temperature dependant resistivity.  Even at absolute zero, the metals have non zero resistivity which is due to presence of impurities.


It is tangible stuff; what when one can touch and sense with your hands and so a physical thing.


The CGS unit of magnetic flux defined as the flux through one square centimeter normal to a magnetic field of 1 Gauss.

Mcleod Gauge

A McLeod gauge is an absolute pressure standard to which many other vacuum gauges are calibrated.  It will accurately measure the total pressure of non-condensable permanent gases (i.e. hydrogen, nitrogen, oxygen, etc.) in a vacuum system, but will not correctly measure condensable vapors if present. This form of vacuum gauge was invented in 1874 By H. G. McLeod to measure pressures of the order of 10-2 to 10-7 Torr. The calibration of the gauge for non-condensable gases is based upon Boyles’ law for gases and therefore measurement of the volume of the glass bulb and the volume per unit length or bore of the capillary tubes is made with high precision.


The mean, except in statistics courses and scientific journals, is more commonly known as the average. The mean is perhaps the most widely used and reported measure of central tendency. The mean is quite simple to calculate: Simply add all the numbers in the data set and then divide by the total number of entries. The result is the mean of the distribution.

Mean Free Path

It is a microscopic quantity of a matter which is defined as average distance travelled by an atom/molecule/electron between two successive collisions in a medium.

Mean Deviation

The average of the deviations of the individual values from the arithmetic mean is called mean deviation.

Mean Life (Radiation Physics)

 Reciprocal of decay constant is called average life of radioactive species.

Mechanical Energy

 It is energy possessed by an object by virtue of its kinetic energy or potential energy or combination of   both.

Mechanical Equilibrium

When there is no unbalanced force between system and its surroundings, the system is said to be in mechanical equilibrium.

Mechanical Equivalent of Heat

 It is defined as work done to produce a quantity of heat. It is denoted by ‘J’. J=W/H. In CGS system ‘W’ is ergs, ‘H’ in calories, J= 4.18 Joules/Cal

What is Plasma?

A plasma (or, more properly, an electromagnetic plasma) is a phase of matter that has enough energy for the electrons to separated from the nucleus. It consists of independently moving electrons and nuclei, and thus has some rather interesting properties, such as very good magnetic shielding. It can be found in places such as the center of the sun, and also, in small quantities, surrounding a lightening bolt. 

Many people consider solid, liquid, gas and plasma to be the only four phases of matter. This is not true, as there exist many others, but they are generally more exotic with names like hadron gas or Bose-Einstein Condensate.

Difference between "Mass" "Matter" and "Energy"

Well the fancy of the subject "physics" is unexplainable. Understanding of basic terminology gives immense satisfaction. 

How many of you could differentiate the three terms "Matter", "Mass" & "Energy" which are essential for beginning understanding of physics? 

Let us start explaining things:- "Mass" is an attribute and not a physical thing. Mass is the attribute "inertia" of a physical object or of what ever is contained in a specified region of space. 

"Inertia" is the inherent reluctance to undergo a change in velocity. If one consults the research documents of decade 1900-10, when Einstein and others developed the equation E=mc2, one finds that for those physicists- the word "Mass" was synonym for "inertia". 

"Matter" is tangible stuff; What you can touch and sense with your hands and so a physical thing.Hence all matter has inertia and hence has mass. 

 "Energy" is the ability to do work. It is an attribute to physical object or of whatever is contained in a specified region of space. Three general forms for existence of energy are "Kinetic", "potential", "Radiant". "Kinetic" is the energy associated with motion. 
"Potential energy" is the energy that has potential for being converted to kinetic energy. 
"Radiant energy" is energy of Electromagnetic waves. 

Take a stone and throw into air. The stone which you are able to collect it from ground has got matter as you have touched and sensed it. While moving in air the stone doesn't get blown by wind breeze etc and does possess "inertia". It is moving with a velocity and does has Kinetic energy, at the same time it is at a varying height from ground and hence possess gravitational potential energy.Thus the stone in air has got partly kinetic energy and partly potential energy. Thus "mass' and "energy" exist as attributes of a physical system, just as do color or shape. Mass and energy exist in the same fashion and matter exists in different fashion. Hope this benefits the student community.......Have a nice day