A parallel plate capacitor is charged to a potential difference V by a dc source. The capacitor is then disconnected from the source. If the distance between the plates in doubled, state with reason how the following will change,
(i) electric field between the plates,
(ii) capacitance and
(iii) energy stored in the capacitor.

Explanation

To solve the problem, we will analyze how the electric field, capacitance, and energy stored in a parallel plate capacitor change when the distance between the plates is doubled after being disconnected from the DC source.

### Given:
- Initial potential difference (V)
- Initial distance between plates (D)
- The capacitor is disconnected from the DC source.

### Step 1: Electric Field (E)
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