00:01
An example of electrical work.
00:04
So a reminder about how work is related to change in potential energy.
00:11
So if you're talking about work done by a conservative field, the work is the negative change in potential energy.
00:21
So i'm using you for potential energy.
00:24
And this is the work done by a field such as gravity or an electric field are usually the two examples.
00:33
Meanwhile, if you're talking about a work done by an external agent, i always like that, a thought, but a person or machine that comes in and fights against the field, then the work is the positive change in the potential energy.
00:55
And just as a reminder, the potential energy of a electrical system, the change in electrical potential energy, is simply q times delta v for a point charge, for a small charge or test charge, sometimes they're called, for a point charge in a field.
01:28
Okay, the field, we're using the potential to describe it.
01:35
Anyway, let's suppose that, so here's a case, let's suppose that we have a negative charge.
01:43
I think that's either a negative charge or a positive charge with a blip next to it, but we'll call it a negative charge minus 54 .9 microculems.
01:57
So that is our test charge.
01:59
And it is sitting there in a field...