Two point charges 9 `muC` and `-2muC` are placed at a separation of 20 cm from each other.
(i) Calculate the electric potential energy of this system of two charges.
(ii) What amount of work is required to separate the particles to infinite separation?

Explanation

To solve the problem step by step, we will calculate the electric potential energy of the system of two charges and then determine the work required to separate them to infinite separation.

### Step 1: Identify the given values
- Charge \( Q_1 = 9 \, \mu C = 9 \times 10^{-6} \, C \)
- Charge \( Q_2 = -2 \, \mu C = -2 \times 10^{-6} \, C \)
- Separation distance \( r = 20 \, cm = 0.2 \, m \)

### Step 2: Use the formula for electric potential energy
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