Field Of Uniformaly Charged Disc

A point charge placed on the axis of a uniformly charged disc experiences a force f due to the disc. If the charge density on the disc sigam is, the electric flux through the disc, due to the point charge will be

Find the electric potential at the axis of a uniformly charged disc and use potential to find the electric field at same point.

A charge q is placed at the some distance along the axis of a uniformly charged disc of surface cahrge density sigma . The flux due to the charge q through the disc is phi . The electric force on charge q exerted by the disc is

Calculate electric field at a point on axis, which at a distance x from centre of uniformly charged disc having surface charge density sigma and R which also contains a concentric hole of radius r.

At which distance along the centre axis of a uniformaly charged plastic disc of radius R is the magnitude of the electric field equal to one-half the magnitude of the field at the centre of the surface of the disc ?