What is wave packet?Explain by using necessary diagram.

Explanation

Resultant were obtained by superposition of waves of different wavelengths is called wave packet.
Matter wave associated with electron is not extended in inifinite space.It is a wave packet extended about a central wavelength.
In this condition `Deltax` is not infinite but it has some definite value which depend on range of wave packet.
Also a wave packet does not have definite wavelength but made up of no. of wavelengths about a central wavelength.
With description of wave packet with de-Broglie relation and Born.s probability interpretation reproduce the Heisenber.s uncertaintly principle exactly.
(a)The wave packet description of an electron.The wave packet corresponds to a spread of wavelength around some central wavelength (and hence by de Broglie relation ,a spread in momemtum).Consequently ,it is associated with an uncertainly in position `(Deltax)` and an uncertainly in momentum `(Deltap)`
(b) The matter wave corresponding to a definite momentum of an electrin extends all over space.In this case ,`Deltap=0` and `Deltaxtooo`
Figure (a) shows a schematic diagram of wave packet and figure (b) shows an extended wave will fixed wavelength.
The particle at that point.Probability density means probability per unit volume.Thus ,If A is the amplitude of the wave at a point ,`|A|^(2)DeltaV` is the probability of the particle being found in a small volume `DeltaV` around that point .Thus ,if the intensity of matter wave is large in a certain region,there is greater probability of the particle being found there than where the intensity is small.