Magnitude of the angular momentum?

[erik-the-red]

Question:

A particle with charge 6.40 * 10^(-19) C travels in a circular orbit with radius 4.68 mm due to the force exerted on it by a magnetic field with magnitude 1.65 T and perpendicular to the orbit.

It then asks for the linear and angular momentum.

I got the linear momentum by using an equation I found in the text. But I didn't find any equation for the angular momentum, and that is where I'm stuck at.

 

[radou]

Let's start with a definition: http://scienceworld.wolfram.com/physics/AngularMomentum.html" .

 

[erik-the-red]

radou, thanks a lot. I was thinking about $$L = I\omega$$, but I thought that calculating the moment of inertia was probably not the right thing to do in this problem.