The coulomb electrostatic force is defined for

Options

A. two spherical charges at rest
B. two spherical charges in motion
C. two point charges in motion
D. two point charges at rest

Answer

To solve the question "The Coulomb electrostatic force is defined for what?", we will analyze the concept of electrostatic force and the conditions under which it applies.

### Step-by-Step Solution:

1. **Understanding Electrostatic Force**:
- The term "electrostatic" refers to forces between charged objects that are not in motion. This means that the charges involved are at rest.

**Hint**: Remember that "electrostatic" implies that charges are stationary.

2. **Identifying the Nature of Charges**:
- Coulomb's law describes the force between two charged objects. It is important to note that this law is applicable specifically to point charges, which are idealized charges concentrated at a single point in space.

**Hint**: Consider the definition of point charges and how they differ from extended charges.

3. **Coulomb's Law Formula**:
- According to Coulomb's law, the electrostatic force (F) between two point charges (Q1 and Q2) separated by a distance (R) is given by the formula:
\[ F = k \frac{Q1 \times Q2}{R^2} \]
- Here, \( k \) is Coulomb's constant. This formula shows that the force is inversely proportional to the square of the distance between the charges.

**Hint**: Recall the formula and its components to understand how the force behaves with distance.

4. **Limitations of Coulomb's Law**:
- Coulomb's law is only valid when dealing with point charges. For extended objects, the distribution of charge affects the calculation of force, making Coulomb's law inapplicable in its simple form.

**Hint**: Think about how the distribution of charge in extended objects complicates the calculation of forces.

5. **Conclusion**:
- Therefore, we conclude that the Coulomb electrostatic force is defined for two point charges that are at rest. This leads us to the correct answer.

**Final Answer**: The Coulomb electrostatic force is defined for two point charges at rest.

### Summary:
The Coulomb electrostatic force applies to two point charges that are stationary. It is not valid for charges in motion or for extended charge distributions.