# Faraday's Law Lecture Error?

1. Jun 27, 2011

### teroenza

Hello,

At approximately 4 min 48 sec. the professor indicates that the surface for the surface integral is closed. This contradicts my albeit limited knowledge in which the magnetic flux through a closed surface is zero (Gauss's law for magnetism). Did he make an error of is my understanding incomplete?

Thank you

2. Jun 27, 2011

### Andrew Mason

I assume that your link is to #11 video.

He is saying that the rate of change of the flux through the area defined by the closed path is equal to the line integral of the electric field around that path. So the area he is speaking about has a single surface - the area enclosed by the path.

AM

3. Jun 27, 2011

### teroenza

I apologize, yes I meant video number 11 of the Yale phys 201 series. This link did not copy-and-paste correctly.
I do not quite understand your response. He drew a circle on the double integral symbol of the flux side of the equation, which would make it a closed surface, and thus make magnetic flux emanating from it equal to zero by Gauss's law, correct?

Last edited: Jun 27, 2011
4. Jul 4, 2011

### tmiddlet

You're right:
The closed loop integral of E dot dl is minus the change in magnetic flux through the open surface attached to the loop.