IIT JEE , AIEEE Forum - Physics , Electricity

nishant_delhi

Hey guys! I was studying abt capacitors and i come across this :

Some +ve charge is given to metal 'A' which induces some -ve charge on 'B' and due to this -ve charge potential of A is greatly reduced.

the ques. is how it get reduced and wht potential exactly means here.

Plz.. reply rates assured

varun.tinkle

SIMPLE
SUPPOSE A CHARGE OF 5 uC IS SUPPLIED TO THE POSITIVE PLATE AND IT GETS DIVIDED INTO 2 PARTS
SAY 2.5 AND 2.5
BUT THE CHARGE OF A CAPAC IS THE CHARGE ON ONE OF ITS SIDES NOT THE SUM OF THE CHARGES
SO V=2.5/C
EARLIER IT WAS 5/C
PLZ RATE ME IF U FIND ME USEFUL
!!!!CHEERS!!!!!!

indrajeet_bariar

see, potential is a scaler quantity.Hence for superposition we have to apply scaler addition, taking sign of the charge into consideration.now assume a point P on the surface of the metallic plate.When the plate B is not there, the only cause of potential at pont P will be due to charges on the plate A itself. But when the plate B is kept near it, the potential at point P is also due to charges on plate B.This addition potential will be both due to -ve charge on inner plate and +ve charge on outer plate, but since -ve charge is nearer the effect of it will be more. Now considering the sign of effective charge we can say tht the potential of point P will be reduced.
And the potential here means work done to bring a unit positive charge from infinity to the suface of tht plate.
plz.. rate if satisfied.

angel.angelina

charge on A induces opposite charge on B . this is a capacitor . Net charge on system is zero. In absence of B potential of A was only due to charge on A . But in presence of B potential due to B should be considered. Initially A was at heigher potential . as you know charge flow from heigher to lower potential. hence potential of A get reduced. PLEASE RATE IF SATISFIED.

v.sabarish

potential is inversely proportional to distance....
a dissimilar charge is induced at a shorter distance and a similar charge at a larger distance... hence... opposite potential dominates and net potential on surface is reduced

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