Question Detail
Question
Two identical charges of $5 \mu\text{C}$ each are placed $0.15 \text{ m}$ apart. Calculate the work required to bring these charges from infinity to this distance (which is equal to the potential energy).
Correct Answer
Option B is the correct answer.
Detailed Explanation
Convert microCoulombs to Coulombs: $5 \mu\text{C} = 5 \times 10^{-6} \text{ C}$. $U = \frac{(9 \times 10^9) \cdot (5 \times 10^{-6}) \cdot (5 \times 10^{-6})}{0.15} = \frac{0.225}{0.15} = 1.5 \text{ J}$.
Hint
Don't forget to convert $\mu\text{C}$ to $\text{C}$ by multiplying by $10^{-6}$ before plugging into the formula.