Two point charges 4Q, Q are separated by 1m in air. At what point on the line joining the charges is the electric field intensity zero ?
Also calculate the electrostatic potential energy of the system of charges, taking the value of charge, `Q=2xx10^(-7)C`.

Explanation

To solve the problem step by step, we will first find the point where the electric field intensity is zero and then calculate the electrostatic potential energy of the system of charges.

### Step 1: Understanding the Setup
We have two point charges:
- Charge 1: \(4Q\)
- Charge 2: \(Q\)

These charges are separated by a distance of 1 meter in air. We need to find the point on the line joining these charges where the electric field intensity is zero.
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