jk4

**[SOLVED] particle in a box**

**1. Homework Statement**

An electron moves with a speed of v = [tex]10^{-4}[/tex]c inside a one-dimensional box of length 48.5nm. The potential is infinite elsewhere. What is the approximate quantum number of the electron?

**2. Homework Equations**

[tex]E_{n} = \frac{n^{2}\pi^{2}\hbar^{2}}{2mL^{2}}[/tex]

n = 1, 2, 3, . . .

[tex]E = \gamma mc^{2}[/tex]

**3. The Attempt at a Solution**

I was trying to solve it by finding the total energy of the electron, then using the first equation I stated using the total energy as "En". Then I would try and solve for n but I get a very different number. The answer is supposed to be 4.