First page Back Continue Last page Overview Image
- The figure shows one such ring, with radius r and radial width dr. If is the charge per unit area, the charge on the ring is
- PHY102 Physics II © Dr.Cem Özdoğan
- 22-7 The Electric Field due to a Continuous Charge
- We need to find the electric field at point P, a distance z from the disk along its central axis.
- Integrating: We can now find E by integrating dE over the surface of the disk— that is, by integrating with respect to the variable r from r =0 to r =R.
- This is the electric field produced by an infinite sheet of uniform charge.
- If we let R →∞, while keeping z finite, the second term in the parentheses in the above equation approaches zero, and this equation reduces to
- Define & Adding: Divide the disk into concentric flat rings and then calculate the electric field at point P by adding up (that is, by integrating) the contributions of all the rings.