Aparticular conductor has 3.0 × 10^27 mobile electrons per cubic meter. the material is in the shape of a cylinder of length 6.0 cm and diameter 1.0 cm. when the bar is connected to a battery with an emf of 2.5 v, a current of 5.0 ma begins to flow.
what is the resistivity of the bar?

Explanation:

Given

Length of cylinder

diameter of cylinder

Area of cross-section

current

R is also given by

where

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