Two sphere of masses `m` and `M` are situated in air and the gravitational force between them is `F`. The space around the masses in now filled with a liquid of specific gravity `3`. The gravitational force will now be

Answer

To solve the problem, we need to understand how the gravitational force between two masses behaves when the medium surrounding them changes. Let's break it down step by step.

### Step-by-Step Solution:

1. **Understanding Gravitational Force**:
The gravitational force \( F \) between two masses \( m \) and \( M \) separated by a distance \( R \) is given by Newton's law of gravitation:
\[ F = \frac{G \cdot m \cdot M}{R^2} \]
where \( G \) is the universal gravitational constant.

2. **Identifying the Effect of Medium**:
The problem states that the space around the masses is filled with a liquid of specific gravity 3. However, it is important to note that the gravitational force is independent of the medium in which the masses are placed. This means that changing the surrounding medium does not affect the gravitational attraction between the two masses.

3. **Conclusion on Gravitational Force**:
Since the gravitational force depends only on the masses and the distance between them, and not on the medium, the gravitational force when the space is filled with the liquid will still be:
\[ F' = F \]
Therefore, the gravitational force remains the same even after the medium is changed.

### Final Answer:
The gravitational force between the two spheres when the space is filled with a liquid of specific gravity 3 will still be \( F \).

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