HEISENBERG UNCERTAINTY PRINCIPLE
According to Bohr’s Atomic Theory, an electron was considered to be a particle but according to De-Broglie electron also behaves as a wave. Due to this dual nature of electron Heisenberg gave a principle known as Heisenberg’s Uncertainty Principle in 1925.
It states that:
“It is impossible to calculate the position and momentum of a moving electron in an orbit simultaneously.”
“If uncertainty of position of an electron, moving in an orbit, becomes zero then the uncertainty of its momentum becomes infinite.”
It means that if one was known exactly then it would be impossible to find out the other exactly. Therefore if the uncertainty in the determination of momentum is ∆P and the uncertainty in position is ∆x then, according to the principle, the product of these two uncertainties may be written as:
∆P . ∆x = h
So if one of these uncertainties is known exactly then the uncertainty in its determination is zero and the uncertainty of the other will become infinite. The Heisenberg’s Principle, therefore explains the basic incompleteness of the Bohr’s Atomic model.