# Probability for a particle in a box

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1. Nov 30, 2014

### rmjmu507

1. The problem statement, all variables and given/known data
A particle in a box of width 2a is in a state $\psi=\frac{1}{\sqrt{2a}}$ for |x| less than or equal to a and 0 for |x| greater than a. What is the probability of finding the particle in [-b, b] inside the box? What is the probability of finding the particle with momentum p inside the box?

2. Relevant equations
None

3. The attempt at a solution
So, for the probability of finding the particle in [-b,b], I simply integrated the function from -b to b and found that the probability is b/a.

I'm not sure how to approach the probability calculation for finding the particle with momentum p though...can someone please provide some guidance?

2. Dec 1, 2014

### Orodruin

Staff Emeritus
What measurement values of the momentum operator are possible?