Question

I got 1.63 x 10^8 N/C for the first one so i think it threw everything off

Consider a disk of radius 2.2 cm with a uniformly distributed charge of +4.4 mu C. Compute the magnitude of the electric field at a point on the axis and 3.6 mm from the center. The value of the Coulomb constant is 8.98774 Times 10^9 N m^2 / C^2. Compute the field from the near-field approximation x << R. Compute the electric field at a point on the axis and 44 cm from the center of the disk. Approximate the field by treating the disk as a +4.4 mu C point charge at a distance of 44 cm.

Answer 1

The magnitude of electric field due to a uniformly charged disc at a distance z directly above the centre of the disc is given by R Radius of the disc ơ Surface charge density (Q Total charge) 2 R a. At z-3.6 mm 3.6x10-3 E 2x8.98x10x-:41 2x8.98x10, 4.4x10-5 % 3.14x0.22° E | (3.6x10) 0.222 511.46x10 N/C