Question1

A single point charge (q = +1.85 µC) is fixed at the origin. An imaginary spherical surface of radius 3.00 m is centered on the x axis at x = 5.06 m.

plan electric field lines for this charge (in two dimensions) assume twelve equally spaced field lines in the xy plane leave the charge location, with one of the lines in +x direction. Do any lines enter the spherical surface? If so, how many? Do any lines leave the spherical surface? If so, how many? Counting the lines that enter as negative and the ones that leave as positive, what is net number of field lines that penetrate the spherical surface?

What is the net electric flux through this spherical surface?

Question2

A non conducting disk of radius R lies in the z = 0 plane with its center at the origin. The disk has a uniform surface charge density σ. Find out the value of z for which Ez = σ/ (4ε0). Note that at this distance, the magnitude of the electric field strength is half the electric field. Strength at points on the z axis that is very close to the disk.