is gauss theorem applicable for insulators and semi conductors .
qn. 4 u >>>
a solid sphere has +ve charge uniformly distributed inside it . a spherical portion is cut out off the sphere and a cavity hence created . find the nature of electric field inside the cavity .
Yes. gauss's thrm is applicable for insulators n semi-conductors.
The electric field is zero at all points inside the cavity, if the solid sphere is a conductor.
the answer is that the +ve charges induce negative charges and net field is -ve . but i want a little more explaination and reason so as to why charges are induced and from where these charges come from .
See there is nowhere given that the sphere is conductor so it is not necessary that the charges will come on the outer surface(Given in the ques. itself).
Now when a cavity is cut inside the spherical shell some charges reside on its boundary which result in a
UNIFORM electric field throughout the cavity
u say uniform electric field i say its nature is negative .
this is that 100 percentileqn. i saw the soln. but i don get the fact so as to from where these electrons are coming from ???
well the solid sphere is not a conductor ........
and if a conductor charges udnt hve aligned inside it
they ud only exist at surface. so the ans is ritly uniform electric field thru out........
and the derivation of it can be done using superposition principle ....
yes gauss theorm is valid for insulators ans semiconductors.SEE its derivation in any book; we didnt take conductors as our assumption anywhere.
field inside cavity is uniform. this can be prove dby considering cavity=+ve charge +-ve charge.
Consider any pt P in cavity.center of sphere exert attractive force on pt P(field towardsitself) and center of -ve charge(ie center of cavity ) exert repulsive force(field away from itself). By simple vector calculations we can prove electric field is uniform.
if u couldnt follow plz let me know. I would attach figure along with it
Well...considering the sphere is a conductor the charge will always distribute itself on the surface and even if there is a cavity created, the field inside the sphere will be ZERO. And yeah gauss's law can be applied for both semi-conductors and insulators ...thrs no reason why it cannot be.
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