Three charges are located at the vertices of a triangle, as shown. an isosceles triangle lying on its side. the two charges at the corners of the base of the isosceles triangle are labeled +5 c and +10 c. the top of the triangle is labeled +4 c with 4 vectors from it. the one east is labeled y, the one west is labeled w, the one northeast is labeled x and the one southeast is labeled z. which vector best represents the net force acting on the +4 c charge in the diagram? w x y z

measure their densities same density, same sub

electromagnetic shielding is the practice of reducing the electromagnetic field in a space by blocking the field with barriers made of conductive or magnetic materials. shielding is typically applied to enclosures to isolate electrical devices from their surroundings, and to cables to isolate wires from the environment through which the cable runs. electromagnetic shielding that blocks radio frequency electromagnetic radiation is also known as rf shielding.

the shielding can reduce the coupling of radio waves, electromagnetic fields and electrostatic fields. a conductive enclosure used to block electrostatic fields is also known as a faraday cage. the amount of reduction depends very much upon the material used, its thickness, the size of the shielded volume and the frequency of the fields of interest and the size, shape and orientation of apertures in a shield to an incident electromagnetic

from wikipedia