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sydzhr
Hi, can someone please give a good definition on uncertainty?
No observation which we take is exact and so it always has some error with it. For example we cannot measure distance in pico meter as we don't have such a small scale and also cannot make it. Thus, it is clear that there is some error attached with every observation. Heisenberg's principle state that the more precisely we know the position of a particle, the more uncertain is its velocity and vice-versa. This might be due to the fact that we would use a light source to find the position of the particle. Now if we want to know its position more accurately we'll have to use a light source with lower wavelength. This light will also have more energy (due to higher frequency) and hence would give some of its energy to the particle on interaction thus increasing its velocity.
In quantum mechanics, the uncertainty principle is any of a variety of mathematical inequalities asserting a fundamental limit on the precision with which certain pairs of physical properties of a particle, such as position x and momentum p, can be simultaneously known. The more precisely the position of some particle is determined, the less precisely its momentum can be known, and vice versa..The original heuristic argument that such a limit should exist was given by Werner Heisenberg in 1927. A more formal inequality relating the standard deviation of position σx and the standard deviation of momentum σp was derived by Kennard later that year (and independently by Weyl in 1928), \sigma_{x}\sigma_{p} \geq \frac{\hbar}{2}, where ħ is the reduced Planck constant.
UNCERTAINTY IN SIMPLE TERMS IS JUST THE ERROR!! THE POSSIBLE DEVIATION OBTAINED IN THE EXPERIMENT LEADING TO UNACCPTABLE RESULTS!
Yup. you cant know anything to an accuracy better than 'h' 6.626 x 10^-34Js.
Or h/2pi. So there you go. This also stands for position and velocity and energy and time and also, acceleration and momentum..