I Wonder I wonder why the grass is green, and why the wind is never seen ? Who taught the birds to build a nest, And told to trees to take a rest ? O, When the moon is not quite round, Where can the missing bit be found ? Who lights the stars, when they blow out, And makes the lightning flash about ? Who paints the rainbow in the sky, And hangs the fluffy clouds so high? Why is it now, do you suppose, That Dad won't tell me , if he knows? by Jeannie Kirby
The French physicist Henry Becquerel was engaged in furnishing a relation between X-rays and luminescence exhibited by Uranium salts. Hindi video lecture dekhne k lie 👇👇👇 One day in 1896 by chance he wrapped a photographic plate in a thick black paper and placed a small crystal of potassium uranyl sulphate upon the black paper.Next day to his surprise he saw that the photographic plate had darkened at some places. Becquerel concluded that the uranium salt had emitted a kind of ray which could penetrate the thick black paper, like X-rays. Discovery of Radioactivity After thorough Investigation on the nature and the characteristics of the rays he came to the following conclusions :--- 1. Uranium salts spontaneously emitted a kind of that could not be controlled by any physical or chemical condition. 2. The ray could fog photographic plate wrapped in black paper and could pass through thin sheets of metal foil which are ...
●Difference between Orbit and Orbitals :– Video lecture dekhne k lie, YouTube channel ko subscribe kijiye👇👇👇 https://youtu.be/QZODCfNWW0w 1. Orbit- it is a definite circular path followed by an electron. where as Orbital- It is a region in space around the nucleus where the probability of finding the electron is maximum. 2 . Orbit- The shape of an orbit is circular or elliptical. where as Orbital- Different orbitals have different shapes e.g., s-orbitals are spherical, p-orbitals are dumble shaped etc. 3 . Orbit- An orbit can have more than two electrons, an orbit can accommodate maximum 2n² electrons. e.g 3 rd orbit (n=3) can accommodate maximum 18 electrons. where as Orbital- An orbital cannot accommodate more than two electrons. 4 . Orbit - Two orbits in an atom cannot ha...
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