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

### Step-by-Step Solution:

#### Part 1: Finding the Point Where Electric Field Intensity is Zero

1. **Identify the charges and their positions:**
- Charge \(4Q\) at position \(A\)
- Charge \(Q\) at position \(B\)
- Distance between \(A\) and \(B\) is \(1 \, \text{m}\)
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