Two large metal plates with surface charge densities `+sigma` and `-sigma` are separated from each other by a distance of d. Find the force per unit area acting between them.

Explanation

To solve the problem of finding the force per unit area acting between two large metal plates with surface charge densities \( +\sigma \) and \( -\sigma \), we can follow these steps:

### Step 1: Understand the Setup
We have two large parallel metal plates:
- Plate 1 has a surface charge density \( +\sigma \).
- Plate 2 has a surface charge density \( -\sigma \).
- The distance between the plates is \( d \).

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