I am an experimental particle physicist, traveler, teacher, researcher, scientist and communicator of ideas.
I am a quarkist and a bit quirky ! Hypothesis non fingo, eppur si muove, dubito cogito ergo sum are things that turn me on !
Researcher in experimental high energy physics (aka elementary particle physics; like “quarks, leptons & mesons and baryons”) … Teacher of Physics (and occasionally chemistry and maths) Blogger (check my website; mdashf.org) !
Love to read read and read but only stuff that interest me. Love to puff away my time in frivolities, just dreaming and may be thinking.
Right now desperately trying to streamline myself.
i. We assume a dilute gas which is enclosed by a thermally insulated container on all sides.
Dilute gas in a thermally insulated container: Dilute means concentration of gas molecules is low. Insulated implies there is no reasonable flow of heat energy across the walls of the container.
ii. Each molecule is assumed to be a hard sphere which moves randomly in all directions such that its velocity vary from – infinity to + infinity.
Hard sphere: Remember a hard sphere is a classical analogy of a rigid sphere whose surfaces do not deform when an external object comes into contact. This essentially means the incoming object is scattered elastically that is without loss of kinetic energy, only momenta magnitude and directions are changed in accordance with the conservation of linear momentum.
iii. When molecules collide they do not lose energy or time. They bounce off each other so that ‘energy’ and ‘momenta’ are conserved.
We would like to obtain an expression for velocity distribution function. That is we would like to know the fraction of molecules having velocity between v to v+dv for all possible values of velocity.
For this we assume an ensemble of molecules in equilibrium. The ratio of number of molecules in a velocity range to the total number of molecules N gives the probability of finding a molecule in that velocity range.
v. The “phase space” of the ensemble of molecules is defined by a 6 N dimensional space, which constitutes of 3 N spatial components and 3 N velocity components of the N molecules in equilibrium. For a more advanced concept of phase space check the following statistical mechanics lecture.
If you would like to become a nuclear physicist, what you would like to know about the nucleus first?
A. structure of the nucleus
Every atom consists of a dense positive central core of mass, known as nucleus. Its size is much smaller compared to the size of the atom, nut nonetheless it contains almost all of the mass of the atom.
The nucleus is made of only neutrons and protons. — These are collectively known as nucleons.
Nucleons are not the smallest constituents of matter. — In-fact nucleons are made of different combinations of 3 quarks, of which only two of the quarks can be of the same type.
Combinations of 3 quarks which form into a bound state of material system are known as baryons. We will study about baryons in the last part of this lecture series.
Thus baryons are a naturally occurring collective matter, built from 3 quarks, where the 3 quarks interact among each other, but can’t escape this bound state of formation, even under the impact of tremendous force.
This fact is known as asymptotic freedom, such freedom is only a dream for them, and for us. This is possible in principle, when the distance of separation between them can be made infinite, in order to weaken the existing attractive force between them, to zero.
Analog electronics and applications
Conductors, semiconductors and holes as charge carriers
Topics covered in this lecture
D. Intrinsic semiconductors
Conductors: A conductor is the name of a material which is a good conductor of electricity. Copper ( Cu ), Silver ( Ag ) and Gold ( Au ) are examples of materials which are good conductors of electricity, in other words they are known as conductors.
A natural question arises as to why copper is a good conductor of electricity. Such a fact can be understood from its electronic configuration.
Electronic configurations are a good way to understand the physical as well as chemical properties of materials. A great deal of our modern understanding of materials and their properties are based on the detailed electronic configuration facts of the same.
The copper has 29 electrons in its atom. That means it has an equal number of protons. It has two isotopes, one has 34 and the other has 36 neutrons. Isotopes are the same chemical element having 2 or more than 2 different types of nuclei, due to difference in the number of neutrons. As a whole copper atom is electrically neutral.
The 29 electrons are distributed into shells or orbits. Consequently the first orbit has 2, 2nd orbit has 8 and 3rd orbit has 18 electrons. There is only 1 electron in the outermost orbit of the copper atom.
I was doing some research on optimization of my website. This is what I found.
Good news: My website is optimized for mobile devices, 15% better than some of the best blogs around the world. That means if you have been accessing my websites on your mobiles, you have been happy about your loading experience.
Bad news: My website optimization for desktop is 25% worse than these other sites.
If you have accessed my website from a desktop computer please don’t use curse words.
I am trying to fix the issues. — Its due to 3rd party rendering issues, like Java script and CSS styling codes.
Fundamental types of crystal lattices and their symmetry operations.
a. Types and classes of crystals,
b. Symmetry operations in crystals
In this lecture we will follow through our basic knowledge gained in the last lecture. — lecture — I, II, and shed light on the most interesting properties of crystal lattices, viz. their symmetry properties. Based on their properties we will classify them into various types and classes.
ii. Lattices satisfy additional symmetry operations. But due to the constraint of translational symmetry the total number of symmetry operations that the lattices can satisfy is reduced to a minimum.
iii. This means in 2-dimensional lattice constructs we have only 5 types of lattices which satisfy additional symmetry operations. In 3-dimensional geometry there are a total of 14 classes of lattices.
iv. Thus in 3-dimensional lattices the 14 classes of Bravais lattices are categorized into 7 types or systems of fundamental lattices.
v. The extra symmetry operations are
inversion about a space point and
reflection about a plane passing through a lattice point or
their possible combinations.