# Homework Help: Help on 2 quantum mechanics of atoms problems

1. Aug 5, 2004

### supermenscher

A proton is traveling with a speed of (6.550+/- 0.010)e5 m/s. With what maximum accuracy can its position be ascertained.

I know that p=mv and x=p/h but what do I do with the +/- 0.010, that is the part that confuses me.

How many electrons can be in the n=6, l=4 subshell. I know that l is n-1, so that can be 5, and n=6, so can the atom have 5 electrons?

2. Aug 5, 2004

### Tom Mattson

Staff Emeritus
That's the uncertainty in the velocity.

No. n is not the number of electrons in a shell, it's the energy level. You need to list out the quantum states and count them.

3. Aug 5, 2004

### supermenscher

Yes I know that 0.010 is the uncertainity of the velcoity, but how do I incorporate that into the equation?

4. Aug 5, 2004

### Tom Mattson

Staff Emeritus
Sorry, but I'm not answering that one directly. You should be reading the book.

Now think: What principle in quantum mechanics expresses a mathematical relationship between uncertainty in momentum and uncertainty in position?

5. Aug 5, 2004

### Gokul43201

Staff Emeritus
x = p/h ? Not true ! Reread the part about the Uncertainty Principle.

For a given value of 'l', how many values can 'm' take ? For each of these 'm', how many values of 's' can there be ?