Answer to Question #60743 in Physics for Ashish Kumar

Question

Using Heisenberg’s uncertainty principle, explain whether a particle trapped inside a
one dimensional box of finite length, can be at rest.

Answer 1

Heisenbergs uncertainty principle states that the more precisely the position of some particle is determined, the less precisely its momentum can be known, and vice versa. The finite length of box means that the uncertainty of position is bound from above and hence the uncertainty of the momentum must be bound from below. It can be smaller then some value. This means the particle always have some velocity, it will be of order of that uncertainty.