The correct option is **B. The electrostatic force can be either attractive or repulsive, while the gravitational force is always attractive.** ### Detailed Explanation: 1. **Understanding Electrostatic Force:** - The electrostatic force is described by Coulomb's Law, which states that the force \( F \) between two charged particles is directly proportional to the product of the magnitudes of their charges \( q_1 \) and \( q_2 \), and inversely proportional to the square of the distance \( r \) between them: \[ F = k \frac{|q_1 q_2|}{r^2} \] where \( k \) is Coulomb's constant (\( 8.99 \times 10^9 \, \text{N m}^2/\text{C}^2 \)). - This force can be **attractive** (when the charges are opposite, e.g., positive and negative) or **repulsive** (when the charges are the same, e.g., positive and positive or negative and negative). 2. **Understanding Gravitational Force:** - The gravitational force between two masses is described by Newton's Law of Universal Gravitation: \[ F = G \frac{m_1 m_2}{r^2} \] where \( G \) is the gravitational constant (\( 6.674 \times 10^{-11} \, \text{N m}^2/\text{kg}^2 \)). - This force is always **attractive**, meaning it always pulls masses toward each other, regardless of their nature. 3. **Comparison of Forces:** - The key difference highlighted in option B is that the electrostatic force can act in both attractive and repulsive manners, while the gravitational force can only attract. This fundamental difference is crucial in understanding the behavior of charged particles versus masses. ### Why Other Options Are Incorrect: - **Option A: The electrostatic force is always weaker than the gravitational force.** - This statement is incorrect. While gravitational forces are generally weaker than electrostatic forces at the scale of atomic and subatomic particles, the strength of these forces depends on the specific charges and masses involved. For example, the electrostatic force between two protons is significantly stronger than the gravitational force between them. - **Option C: The gravitational force is dependent on the charge of the objects, while the electrostatic force is dependent on their mass.** - This statement is misleading. The gravitational force depends solely on the masses of the objects, while the electrostatic force depends on the charges. Gravitational force does not involve charge at all, and electrostatic force does not involve mass. - **Option D: The electrostatic force affects only charged particles, while the gravitational force affects all objects with mass.** - While it is true that the electrostatic force acts only on charged particles, the gravitational force also affects all objects with mass. However, this option does not address the comparative nature of the forces, which is the focus of the question. ### Summary of Key Points: - The electrostatic force can be attractive or repulsive, depending on the nature of the charges involved. - The gravitational force is always attractive, pulling masses toward each other. - The strength of the electrostatic force can be much greater than the gravitational force, especially at small scales. - Understanding the nature of these forces is crucial for analyzing interactions in physics, particularly in fields like electromagnetism and astrophysics.