A solid metal sphere carries +q charge. What is the electric field magnitude inside the sphere?

A square plate of copper with 55.0 cm sides has no net charge and is placed in a region of uniform electric field of 75.0 kN/C directed perpendicularly to the plate. (a) Find the charge density of each face of the plate. |nC/m² nC/m? (b) Find the total charge on each face. nC nC

A semicircle of radius a is in the first and Figure second quadrants, with the cen- ter of curvature at the origin. Positive charge +Q is distrib- uted uniformly around the left half of the semicircle, and nega- tive charge -Q is distributed uniformly around the right half of the semicircle (Fig. P21.86). What are the magnitude and direction of the net electric field at the origin produced by this distribution of charge? +Q

What should be the direction and magnitude of the vertical electric field that will balance the weight of a plastic sphere with the charge Q= +1.5 nC and mass m= 1.8 g? 3.2 x 10^5 N/C positive y-direction 1.2 x 10^6 N/C in +y-direction 1.2 x 10^6 N/C in negative y-direction 3.2 x 10^5 N/C in negative y-direction