Assertion : Gravitational force between two masses in air is F. If they are immersed in water, force will remain F
Reason : Gravitational force does not depend on the medium between the masses.

Options

A. If both assertion and reason are true and reason is the correct explanation of assertion
B. If both assertion and reason are truebut reason is not the correct explanation of assertion
C. If assertion is true but reason is false
D. If both assertion and reason are false.

Answer

To solve the given question, we need to analyze both the assertion and the reason provided.

### Step-by-Step Solution:

1. **Understanding the Assertion**:
- The assertion states that the gravitational force between two masses in air is F, and if they are immersed in water, the force will remain F.
- This implies that the gravitational force does not change when the medium changes from air to water.

2. **Understanding the Reason**:
- The reason states that gravitational force does not depend on the medium between the masses.
- This is based on the universal law of gravitation, which states that the gravitational force (F) between two masses (m1 and m2) is given by the formula:
\[ F = \frac{G \cdot m_1 \cdot m_2}{r^2} \]
where G is the gravitational constant, m1 and m2 are the masses, and r is the distance between the centers of the two masses.

3. **Analyzing the Independence from Medium**:
- In the formula, G, m1, m2, and r are all independent of the medium in which the masses are located.
- The gravitational force is a fundamental force that acts at a distance and is not affected by the presence of other materials (like air or water) in between the masses.

4. **Conclusion**:
- Since both the assertion and the reason are true, and the reason correctly explains the assertion, we conclude that the answer to the question is:
- **Option A**: Both assertion and reason are true, and the reason is a correct explanation of the assertion.