[DanielGeltman]

Hey everyone,

I have a problem figuring out the shape factor in the following problem:



"Surfaces 1, 2 and 3 are very long (I assumed infinite..)- surfaces 1 and 2 are identical plates and surface 3 is a quarter of a cylinder. There is vacuum between the surfaces.
What is the value of the shape factor F33? (That's not the real question but that's where I had a mistake)"

So.. I decided to use the following figures:



If we assume that there is an inner cylinder of infinitesimal radius we'll find out that the shape factor F33 is 1, but since we have only quarter of a cylinder I assumed that the shape factor F33 would be 0.25.

I was wrong but don't know why. I also don't know the real shape factor-just that it's not 0.25.

Could you please help me?