(a) briefly describe the physical origin of bound currents in magnetised materials consider a thin slab of material with uniform magnetisation m. with the aid of a diagram and a qualitative argument, show that the volume bound current density is [5] 3. zero (b) a thin conducting cylindrical shell (or pipe) of radius a and infinite extent is symmetrical about the z-axis. it is surrounded by a linear magnetic material extending out to a cylindrical radius b in which the magnetic susceptibility varies smoothly with cylindrical coordinate as xm(s)= xoa2/s2 for a < s

im not to sure what it is

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

myth. it was once thought that animals, including cats and dogs, could only see in black and white. however, scientists have proven this to be a myth. in all animals, including humans, the perception of colour is determined by the presence of cells in the eye called cone photoreceptors.