That's that rho of s

1. Sep 7, 2013

anhnha

Please help me. What does the Prof. Walter Lewin mean by this "that is that rho of s"?

2. Sep 7, 2013

Pythagorean

I think he starts talking about it around 8:30 and eventually makes his way to the right end of the board around 9:30. He has an electric field dependent on rho_s I think he meant "rho sub s" (rho with subscript s).

3. Sep 7, 2013

anhnha

Thanks. Can you explain why the positive or negative of these wires are related to the rho of s?

4. Sep 8, 2013

Any help?

5. Sep 8, 2013

Pythagorean

I don't remember the exact setup and currently on mobile, but I thought the setup was the two wires were each on opposite terminals of a battery, so you have a positive charge on one wire and a negative on the other.