Question:medium

Two point charges \( +2 \, \mu\text{C} \) and \( -3 \, \mu\text{C} \) are placed 10 cm apart in vacuum. What is the electrostatic force between them?

Show Hint

Remember: Coulomb's law is used to calculate the electrostatic force between two point charges: \( F = k \frac{|q_1 q_2|}{r^2} \).
Updated On: Nov 26, 2025
  • 4.5 N
  • 9 N
  • 18 N
  • 2.25 N
Hide Solution

The Correct Option is B

Solution and Explanation

Given: \( q_1 = +2 \, \mu\text{C} = 2 \times 10^{-6} \, \text{C} \), \( q_2 = -3 \, \mu\text{C} = -3 \times 10^{-6} \, \text{C} \), distance \( r = 10 \, \text{cm} = 0.1 \, \text{m} \), and Coulomb's constant \( k = 9 \times 10^9 \, \text{N m}^2 / \text{C}^2 \).

Step 1: Formula for Electrostatic Force Coulomb's law states that the electrostatic force between two point charges is: \[ F = k \frac{|q_1 q_2|}{r^2} \]

Step 2: Substitute the given values Substituting the provided values into the formula:
\[ F = (9 \times 10^9) \frac{|(2 \times 10^{-6})(-3 \times 10^{-6})|}{(0.1)^2} \]
\[ F = (9 \times 10^9) \times \frac{6 \times 10^{-12}}{0.01} \]
\[ F = 9 \times 10^9 \times 6 \times 10^{-10} = 9 \, \text{N} \]

Answer: The electrostatic force is 9 N, corresponding to option (b).

Was this answer helpful?
1