00:01
So in this question, we're thinking about gauss's law for electric surfaces.
00:06
And just to quickly recap what that is, so gauss's law tells us that the integral, double integral over a closed surface of the electric field dotted with the normal to that surface is equal to the triple integral in the volume.
00:31
So it's called the volume v and the surface dv.
00:35
This means the boundary of v of the charge density divided by epsilon naught.
00:47
But we can integrate this side easily to get that the flux of the electric field through a surface is equal to the charge enclosed by that surface divided by epsilon naught, where q is the charge enclosed by s.
01:12
Okay, so that's gauss's law.
01:14
So part one.
01:17
So part one says that if the total electric flux vanishes, so this is the total electric flux.
01:27
So if the total electric flux is equal to zero, then e is equal to zero everywhere on.
01:38
And this is this is not true, not true since e can cancel out in the integral, even if not zero.
02:06
Part two says that if there's no charging closed, then e must be zero everywhere.
02:23
And this is not true as well...