Physics · Electrostatic Potential

Two point charges \( q_1 = 7\ \mu\text{C} \) and \( q_2 = -2\ \mu\text{C} \) are placed at \( (-9\text{ cm}, 0, 0) \) and \( (9\text{ cm}, 0, 0) \) respectively in an external electric field \( E = A/r^2 \), where \( A = 9 \times 10^5\ \text{N}\cdot\text{m}^2/\text{C} \). What is the total electrostatic energy of the configuration?

1. A
   \( 70.0\text{ J} \)
2. B
   \( -0.7\text{ J} \)
3. C
   \( 49.3\text{ J} \)
4. D
   \( 50.7\text{ J} \)