Imagine a solid conductor (an object in which the electrical charges can move ar
ID: 583225 • Letter: I
Question
Imagine a solid conductor (an object in which the electrical charges can move around freely). Now put this object in an external electric field (which is being produced by some source-outiside our object-which we dont care about the details of). a) what do the charges do? They can move within the object, but they cant leave the object. Draw that picture below showing what the charges do. b) ignoring the external field for a moment, the arrangment of charges you just drew produces its own electric field? Draw the picutre again, with that "induced" electric field present c) now include the external field in your consideration. The charges in the conductor feel both the external and induced field. If the external field is bigger than the induced one, what will continue to happen? If the induced field is bigger, what will happen? What is the only stable, equilibrium situation? d) once the conduct has reached equilibrium, what is the total electric field in the middle of the conductor? e) the process (and result) you just described depend on the shape of the conductor? Wy or why not? f) will this process (and result) still happen if we make the conductor hollow? why or why not? g) why might this process and result be useful, espeicaly if we have a hollow conductor?
Explanation / Answer
(a) Electrons will move opposite to the direction of electric field and hence one face of the conductor will negatively charged. Consequntly positive charge will be induced on the opposite face.
(b) Since drawing is not possible here, so, I just explain it. If you ignore the external field, then the induced electric filed will be directed from positively charged face to negatively charged face.
(c) If the external field is bigger than the induced field then negative charge will keep depositing on the negatively charged face and hence positive charge on positive face will also increase. It will keep conitinue untill induced field is equal to the external field. Induced field can never be bigger than external field.
(d) At equilibrium, induced field is equal to the external field. Hence net electric filed inside the conductor will be zero.
(e) No, it doesn't depend on shape of the object because each conductor has characteristic of separation of +ve and -ve charges in presence of external foeld.
(f) This process is usefull because it can be used for electrostatic shielding.