Category: waves

  • Fermat’s Principle, a lecture in optics

    Fermat’s Principle, a lecture in optics

    Optics series lecture, Lecture-III “Geometrical Optics and Fermat’s Principle”. Geometric Optics: When the size of objects that a wave of light interacts with are large compared to the wavelength of light λ, λ can be neglected for practical purposes and the light waves behave like rays of light. Rays of light are geometric line segments…

  • Primary aberration, a lecture in optics.

    Primary aberration, a lecture in optics.

    Lecture-II; delivered on 27-1-2017 In our Lecture-I  we discussed the phenomena of aberrations that arise because of a discrepancy of a first order theory and the 3rd order theory as depicted by the Maclaurin series; where we saw that first order theory represents the so called paraxial optical systems. Please have a look of the linked…

  • Inherent ability = difficulty * accomplishment.

    All of Physics is this “Inherent ability = difficulty * accomplishment”. Thats just intuitive but can easily be seen to correspond mathematically with the Principle of least action. First the edifice: whats the problem? The problem is given you move in straight line when every direction is same around you, which direction will you chose?…

  • Aberrations, a lecture in optics.

    Aberrations, a lecture in optics.

    Optics series Lecture — I Optical Aberrations delivered on 24 – 1 – 2017 — all optics series lectures can be accessed here.  This lecture has been delivered in one of the honors class that I am teaching this semester. You will do really well to read the linked article on Optical path and Fermat’s principle…

  • Waves, particles and Einstein !

    Waves, particles and Einstein !

    Waves are something that have no mass and move at the maximum speed, mass m = 0. speed c = 1. So whats their momentum? p = m.v = 0? Right? No. For pure waves; momentum does not come from mass. It comes only from motion. (pure wave; they do not have mass) For matter…