Classical Physics Essay

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Classical physics is basics of all physics that says matter and energy are two distinct concepts according to newton’s law and theory of electromagnetic radiation. Classical physics is centred on these assumptions, position and momentum of particles can be calculated at any instant when it travels in a trajectory, the energy of a particle may adopt any arbitrary value and waves and particles are separate concepts. However classical physics failed to explain those assumptions on atomic scale because those assumptions made on macro scale which caused some big problems by end of 19th century. Nevertheless problems in classical physics resolvable by modern mechanics which known as quantum mechanics. [1, 2]

Black body radiation

When a black abject has temperature above zero Kelvin does not emits light at all wavelength but it gives out specific light which called blackbody radiation. Hot object emit electromagnetic radiation when atoms vibrates and electrons move around. Blackbody spectrum depends on temperature which means when temperature increases electrons move faster therefore more radiations derive out from black body. Classical physics fails to explain the form of blackbody spectrum. [3]Classical physics suggests when the frequency increases the energy density approach infinity but in fact when frequency increases density tends to decrease. Blackbody spectrum displays the peak of wavelength leans towards short wavelength therefore in high frequency shows short wavelength. [4]

Max Planck introduced Plank’s constant to describe that electromagnetic radiation is emitted in quanta. When an atom absorbs specific energy, an electron move to excited state and then move to the lower energy level by releasing energy. M...

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To conclude, classical and quantum mechanics have many similarity as well as differences. Classical mechanics solves the problem of system in the macroscopic scale whereas quantum mechanics solve the same problem in microscopic scale. At atomic/microscopic scale energy is quantised which means that energy cannot vary continuously, only in quanta. This suggests that is impossible to find the position and momentum of particle at any instant on the atomic scale. In addition it proves that particle cannot adopt any arbitrary value.
Worth to mention, quantum mechanics uses Planck’s constant in all the above equations to give a solution to the problem rise by classical physics. Planck’s constant is very small and only makes a difference about 34th decimal place however it gives a precise result not an average as Newton’s law suggests.
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