You make a position measurement on a particle that is in the

You make a position measurement on a particle that is in the ground state of a harmonic oscillator potential. What is the probability that your position measurement yields a value that is outside the classically-allowed region?

Solution

According to classical mechanics, probability of finding the particle outside the classically allowed region is zero.

But according to quantum mechanics, by considering the wave nature of the particle there is a finite probability of finding the particle outside the classically allowed region.