The electric field E due to a charged circular disk at a point at a distance z along the axis of the disk is given by

where σ is the charge density, εo is the permittivity constant, εo = 8.85 × 10-12 C2/(N m2), and R is the radius of the disk. Determine the electric field at a point located 5 cm from a disk with a radius of 6cm, charged with σ = 300 μC/m2.

4Eo o