# Homework Help: Electron current homework

1. Mar 5, 2008

### tony873004

A single electron in uniform circular motion constitutes an average current around the circle. If the electron moves clockwise with angular speed in a circle of radius r, find the current. Evaluate I if $$\omega=2X10^{16}$$ rad/s and r = 5 nm.

I never used radius r in my answer. This book usually doesn't thrown in irrelavant information in the questions. Did I do this right?

$$\begin{array}{l} I = \left| {\frac{Q}{t}} \right| \\ \\ t = \frac{d}{v} = \frac{{2\pi }}{\omega } \\ \\ I = \left| {\frac{Q}{{\left( {\frac{{2\pi }}{\omega }} \right)}}} \right| = \left| {\frac{{Q\omega }}{{2\pi }}} \right| = \left| {\frac{{ - e\omega }}{{2\pi }}} \right| = \frac{{e\omega }}{{2\pi }} \\ \\ \frac{{1.602 \times 10^{ - 19} {\rm{C}} \times 2 \times 10^{16} {\rm{rad/s}}}}{{2\pi }} = 5.1 \times 10^{ - 4} {\rm{C/s = }}5.1 \times 10^{ - 4} {\rm{A}} \\ \end{array}$$
1. The problem statement, all variables and given/known data

2. Relevant equations

3. The attempt at a solution
1. The problem statement, all variables and given/known data

2. Relevant equations

3. The attempt at a solution

2. Mar 5, 2008

### Shooting Star

Right. The current would be in the CCW direction. (I haven't checked the arithmetical calculation.)

3. Mar 5, 2008

### tony873004

Thanks for verifying that, and reminding me to include direction.