Biology Pre Board | Question paper

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By Arhnav -
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Magnetic field and Field lines The unit of magnetic fields strength is oersted. 😀Q.. Why does a compass needle get deflected when brought near a bar magnet?  😀Q.. Why do the iron fillings arrange in such a pattern? What does this pattern demonstrate?  The magnetic exerts its influence in the region surrounding it. Therefore the iron fillings experience a force.thus exerted makes iron failings to arrange in a pattern.  The reason surrounding a magnet in which the force of the magnet can be detected, is said to have a magnetic field.   The line along which the iron filing a align themselves represent magnetic field lines.  Magnetic field is a quantity that has both direction and magnitude.   The direction of the magnetic field is taken to be the direction in which the North Pole of the compass needle moves inside it. The reactive strength of the magnetic field is shown by the degree of closeness of the field lines.  The field is stronger, that ...
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Photons

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  Photons   Photon, also called light quantum, minute energy packet of electromagnetic radiation. The concept originated (1905) in Albert Einstein’s explanation of the photoelectric effect, in which he proposed the existence of discrete energy packets during the transmission of light. Earlier (1900), the German physicist Max Planck had prepared the way for the concept by explaining that heat radiation is emitted and absorbed in distinct units, or quanta. The concept came into general use after the U.S. physicist Arthur H. Compton demonstrated (1923) the corpuscular nature of X-rays. The term photon (from Greek phōs, phōtos, “light”), however, was not used until 1926. The energy of a photon depends on radiation frequency; there are photons of all energies from high-energy gamma- and X-rays, through visible light, to low-energy infrared and radio waves. All photons travel at the speed of light. Considered among the subatomic particles, photons are bosons, having no ...
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