91Ó°ÊÓ

A force is an influence that can change the motion of an object.A force can cause an object with mass to change its velocity to accelerate. Force can also be described intuitively as a push or a pull.

The parallel plate capacitors are the arrangement of the two electrodes parallel to each other with some dielectric inserted in between them.

Concept:

As equation 24.9 mention, the potential energy stored in a capacitor is given by

Where Q is the magnitude of the charge on each plate, C is the capacitance and V is the potential difference between plates.

As equation 24.2 mention, the capacitance of a parallel plate capacitor is vacuum is given by

Where A is the area of each plate and d is the distance between the two plates. Substituting from the previous calculation then we get

Solution:

When you bring a slab of dielectric close to the charge plates, than the dielectric will Induced charge which opposite the Nearest plate. If the nearest plate was positive then the dielectric will induce negative charge and vice versa. So the attractive force will appear between the bear's plate and the dielectric. The attractive force does positive on the slab as it moves between the two plates. So, the net stored energy in the capacitor will decrease. So, the stored energy in the second case (after adding the dielectric) is less than the stored energy in the first case ( without adding the dielectric).

Therefore The dielectric will induce charge opposite the nearest plate. The attractive force will appear between the nears plate and the dielectric. The net stored energy in the capacitor will decrease. So, the stored energy in the second case (after adding the dielectric) is less than the stored energy in the first case ( without adding the dielectric).