Question

Two parallel metal plates having charges +Q and -Q face each other at a certain distance between them. If the plates are now dipped in kerosene oil tank, the electric field between the plates will :

• A. remain same
• B. become zero
• C. increase
• D. decrease

Answer 1

The correct option is D decrease

The electric field in between two parallel metal plate is $E=\frac{\sigma }{ϵ}=\frac{Q}{Aϵ}$ where $A=$ area of plates and $ϵ=$ permeability of medium in between the plates.
The permeability of kerosene is more that of air. As $ϵ$ increases, $E$ decreases.