# Homework Help: Velocity of electron in a hoop

1. Apr 25, 2010

### Anochaa

1. The problem statement, all variables and given/known data
An electron in a benzene molecule makes a reasonable approximation to an electron
confined to a hoop. If the radius of the benzene molecule is about 5x10-10 m, and the
electron has the lowest allowed angular momentum of h/2π, what is the velocity of the
electron? (You may wish to recall the electron mass is 9x10-31 kg, and angular
momentum is L = rp = rmv.)

2. Relevant equations
I'm not entirely sure.

3. The attempt at a solution
I'm in a really poorly run workshop based class, so we have no text book and the packets we were given are completely not at all helpful here.

2. Apr 25, 2010

### zachzach

The two equations to use are in the problem.

3. Apr 25, 2010

### Anochaa

What do you use for n though?

4. Apr 25, 2010

### ideasrule

Where do you see n?

5. Apr 25, 2010

### Anochaa

"angular momentum of h/2π"

6. Apr 25, 2010

### zachzach

Are you sure that is an n? I believe it is a pi.

7. Apr 25, 2010

### Anochaa

Oooh, my bad. Sorry! That completely threw me off - it looks like an n in the PDF. Now I just feel dumb, haha.

8. Apr 25, 2010

### ideasrule

It definitely is pi.