A parallel plate air-filled capacitor is charged by connecting it across a voltage source for a long time. It is then disconnected from the source and connected across a voltmeter. How the voltage reading in the voltmeter will be affected if a dielectric is inserted between the plates of the capacitor? State your assumptions if any in the explanation.

Explanation

To solve the problem, we will analyze the situation step by step.

### Step 1: Understanding the Initial Conditions
- We have a parallel plate capacitor filled with air, which is charged by connecting it to a voltage source for a long time.
- After charging, the capacitor is disconnected from the voltage source and connected to a voltmeter.

**Hint:** Remember that when the capacitor is disconnected from the voltage source, the charge on the capacitor remains constant.

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