# Quantum number

1. Mar 6, 2006

### UrbanXrisis

a mass of 10^-6 grams is moving at a speed of 0.1 cm/s in a box 1 cm in length. Treating this as a 1-D infinite square well, i am to calculate the quantum number n:

i was wondering if I am setting this up correct:
$$\frac{1}{2} * 10^{-6 }g * 0.1 cm/s = \frac{n^2 \pi^2 \hbar ^2}{2*10^{-6 }g * 1cm^2}$$

2. Mar 6, 2006

### Meir Achuz

Just use v^2 on the LHS.

3. Mar 7, 2006

### UrbanXrisis

so $$E= \frac{n^2 \pi^2 \hbar ^2}{2mL}$$
is really kinetic energy?

4. Mar 7, 2006

### topsquark

Not exactly. E = T + V. But since this is an infinite square well and the region you have has V defined as zero...

-Dan