Aberrations; a lecture in Optics. 1

Optical systems are studied under two assumptions

object point does not lie far away from the axis of the optical system.

rays taking part in image formation make a small angle with the axis of the optical system.

The domain of optics where above two assumptions are valid is called as Paraxial optics. Paraxial systems are highly idealized and in reality do not perfectly represent the situation. The consequential errors in image reconstruction are known as aberrations.
The paraxial assumption can be represented by truncating at the first term of the polynomial expansion of the sin function by the Maclaurin series. More…


A c++ code for calculating pi value. Reply

Finally I am successful in calculating pi value — less than 0.3% error, by using random number generation. Although my computer needs some fixation on its compiler or path definition etc, there are very good online compilers which helps in testing and running c++ codes: try the given link.

Computing the value of pi using std::rand()
Enter number of trials: 10000
Enter number of random (x,y) points per trial: 10
pi = 3.14376 +- 0.00519107
average – exact = 0.00216735
CPU time = 0.004027 secs

Here is the code I found by searching a good deal on the web. Yes I did tinker around but only because my own compiler (Turbo C++ on windows 10, 64 bits) was throwing some exceptions on the included headers.

using namespace std;

double pi_estimate(const unsigned long points) More…

Schrodinger Equation; Concepts and Problems in Quantum Mechanics. Reply

A long and technical discourse on Quantum Wave Function.

A 64 slide presentation styled discourse on the Quantum Wave Function. It consists of detailed solution of 5 important and interesting problems, apart from a threadbare discussion of the concepts.

Addendum to Coriolis Force; Definition of Centripetal Force. 2

We need to understand first that Force can be categorized into two types. One is called tangential or collinear force. This component of the force is always along the direction of motion and changes speed of an object. It can change direction once the velocity of the object has become zero. Its NOT centripetal force. It can never make an object go in a plane or 3 D trajectory, as the motion is limited to only one dimension. The object can only go back and forth.

Now look at the other component. Its called a radial force. Its always perpendicular to the direction of motion. This force is called centripetal force, always. Note that its different from what we call central forces.

In consequence, both tangential and radial forces can be central. More…

This year’s Nobel prize in Chemistry. Reply

What happens when some UV falls on biological molecules? (or any kind) some of these molecules like the wooden pole absorb the energy and there still remains energy which they can emit as visible light. So the UV light kicks the molecules and the molecules in turn emit visible light. This implies that the UV wavelength that the molecules absorbed energy at are very small compared to the wavelength at which they emit visible light. This is always the case.

When we say some materials are fluorescent it means they absorbed higher energy and emitted lower energy radiations of colorful light.

But this has a great deal of application apart from its theoretical interest. More…

The angular parameters of celestial mechanics ! Reply

Define an Hour Circle.

Its a bit tricky to define some astronomical parameters and not run into innocent looking misrepresentations of facts. One needs to cool his amber more times than there are parameters, then one gets a feel where and how to begin and give a good description.

Hour Circle is a GREAT Circle, on a celestial sphere ** that, at the same time, passes through one of the celestial poles. Hence it passes through both of the celestial poles*.

A great circle is a circle that passes on a sphere, so that its radius (or diameter) equals to the radius (or diameter ) of that sphere.

If the great circle goes through one of the poles (– so both poles as an imminent condition of this definition) its also called a meridian and this circles’s angular reference wrt one of all possible meridians is called a longitude angle, or simply longitude. More…