A thin sheet in the shape of an annular semicircle has a positive surface charge density +σ as shown. What is the electric field at point P?
Here is an illustration of the problem:
The Attempt at a Solution
If I draw a gaussian surface somewhere between the point P and the radius a, the charge enclosed would be zero. Can I assume that this would mean that the electric flux through that surface is zero, and, by extension, the electric field experienced at point P is zero, too?
If I'm wrong about the Gauss's law approach, should I instead use a Coulomb's law approach and integrate the electric field generated by the semicircular sheet, minus the electric field generated by the semicircular cavity?