"1. How the idea of quantum mechanics came ? 1. Max Planck introduced the concept of quantization of energy when he was explaining theradiation emitted by blackbody. He considers energy of light as a discrete and formulated aformula E=hf where E stands for energy, h for Planck constant (which tells about themeasurement of angular momentum) and f stands for frequency. So we see that the origin ofquantum mechanics was just an assumption put by Planck and we will see in the questionno.2 how the mere assumptions of Planck revolutionized the quantum mechanics and thewhole world. 2. Write a short notes on the growth of quantum mechannics. 2. Later on Niels Bhor calculated magnetic moment of electron using Planck hypothesis orPlanck assumption. Einstein explained photoelectric effect considering the Planck hypothesis.After that De Broglie made a further progress in quantum mechanics by giving his hypothesisthat every moving particle has wave nature. So it implies that light both properties i.e. particlenatures and wave natures. To explain some physical phenomenon like Compton Effect, blackbody radiation we consider light as a particle and for the phenomenon like diffraction,interference we treat light as a wave. Therefore dual natures of light were established. Planckhypothesis was phenomenological for long period of time. Later on Davisson-Germer wasfinding the angular distributions of electron using nickel foil but accidentally they found thatelectron has wave property as predicted by Davisson and Germer. Schrodinger gave theequation of motion of quantum mechanics; Dirac proposed the concept of anti-particle. KleinGordon gave equation of relativistic quantum mechanics. In this way quantum theory developed enough and it has infinite number of applications in the present real life. It wasoriginated just from the assumption of Planck (which has no experimental verification forlong time) and became a well established theory which totally changed the world! "