Problem On capacitor

[ambuj123]

Hello
i am new to this forum from india and preparing for IIT
:eek:
well i have question
"If a dielectric is placed between two plates of parallel plate capacitor which is isolated and charged the force between plates decrease or remain same . well i found answer in my book that it remains same but i dont know why?
i think it should be reduced becuase induced charges appear on the edges of dieelectric and due to these charges two electric field nullify some of the effect?"
Please help

[Doc Al]

Welcome to PF!

Consider first the capacitor without a dielectric. The charge on one plate creates an electric field which exerts a force on the other plate. That field is proportional to the surface charge density, and is independent of distance. When the dielectric is introduced, induced surface charges do appear on each side of the dielectric, but they cancel. (They effect the field within the dielectric, but not outside it.)

[ambuj123]

THANX for help
:smile: