Question

When a dielectric medium is introduced in a parallel plate capacitor connected with a battery, how will it affect the following physical quantities ?

• charge
• electric field
• electrostatic energy
• potential difference
• capacitance

​​​​

Answer 1

Dear Student,

As we know that when a dielectric slab is introduced in a parallel plate capacitor its capacitance will increase.
That means the charge storing capacity of the capacitor will increases. So, for the given case:

Capacitance of the capacitor increases.
Charge on the plates of the capacitors increases

The capacitor with a dielectric between its plates will charge to the same potential as that of the battery.

Thus, potential across the capacitor will remains unchanged on introducing dielectric slab.

Electric field inside the capacitor with a dielectric between its plates is given as
$E=\frac{E_0}{K}$ where K is the dielectric constant
Thus, electric field decreases.

Energy stored by the capacitor is given as,
$\mathrm{Energy}=\frac{1}{2}QV$
As Q increases, the energy stored by the capacitor also increases on inserting a dielectric slab.

​Regards,