Question

Magnetism - comparing its basic properties with the basic properties of electricity there are similarities, yet distinct differences, seen. Together, electricity and magnetism can be combined to form the more general theory of electromagnetism - seeing that electricity and magnetism can be seen as "opposites sides of the same coin."

One topic that was seen for electricity was the special and common case of electrostatic equilibrium of a conductor. Here several properties were given with the primary one of that the electric field is zero inside a conductor in this state. This is such an important situation for it brings up the concept of "electric shielding", which is utilized in many places, from shielding circuits by placing them inside a metal box (a conductor) to protecting electrical devices inside a special plastic bag to nullifying cell phone signals, etc., inside cars of some transit systems.

With magnetism's connection to electricity, one may wonder if electric shielding has a magnetic counterpart? In brief, yes, but how does it work and how does it compare/contrast with electric shielding? This is what you want to consider, look up, and discuss somewhat briefly, as well as give a real-world application.

Another very common and important concept seen is that of induction with many applications discussed, the two big ones being motors and generators, though, as seen, they are basically the same device working in opposite directions; transformers being another big app.

Here, find an application of induction and briefly discuss. Better, can you find an app. of induction in your field of study?

Please no handwritten or picture responses - only typed replies

Answer 1

Yes, magnetic shielding do exist. It is used where any equipment or sample is prevented from being exposed to any sort of magnetic field. In this case electric shielding cannot be used. Now magnetic shielding can be done in a number of ways which include using the superconducting materials as a magnetic shield because superconductors expels the magnetic fields via Meissner effect during their transition to superconducting state . The effect of magnetic field can also be nulled inside any volume by using the external field created by electromagnetic coils like solenoids etc. This is in contrast to electric shielding where electric field is blocked to enter the shielded area. MuMetal is the most widely used material which is an alloy containing Nickel, Molybdenum and iron for magnetic shielding. Real life applications of magnetic shielding include protecting sensitive transducers like Hall Probes, sensitive electron microscopes , in accelerators etc.

Electromagnetic induction has so many fascinating applications. Lets discuss briefly about one such application to which anyone can relate i.e. debit and credit cards. Have you ever wondered that swiping card which makes our lives so easier actually has physics behind it? The cards have a black magnetic strip at the back which produces electromagnetic induction and card reader uses this to extract the information that is stored on the card.