# B Force between capacitor plates

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1. Jun 30, 2016

### Prateek Kumar Jain

What will happen to the force between the capacitor plates (Will increase or decrease or remain constant) if we introduce a dielectric between them?

As per the answer given the physics text book , the force will remain same? But as per my understanding the force should decrease since electrical field between the plates reduces.

2. Jun 30, 2016

### Paul Colby

The surface charge on a plate is given by the normal $D=\epsilon E$ field. The force is the charge times the $E$ field. For the same amount of charge, the $E$ field is reduced since $\epsilon>1$ so the force will go down.

3. Jun 30, 2016

### sophiecentaur

I can suggest that either the answer you have found is 'in the back of the book' and is wrong due to a simple typo or, if there is a worked example, there may be more to the question than you have stated.
For instance, what is the actual circuit? Is the Capacitor attached to a voltage source or was it charged and then disconnected?