Any solid will sink in water if its relative density is

Options

A. less than unity
B. equal to unity
C. greater than unity
D. infinite

Answer

To determine when a solid will sink in water based on its relative density, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Relative Density**:
- Relative density (RD) is defined as the ratio of the density of a substance to the density of a reference material, typically water for solids.
- Mathematically, it is expressed as:
\[ \text{Relative Density (RD)} = \frac{\text{Density of Substance}}{\text{Density of Water}} \]

2. **Density of Water**:
- The density of water is approximately \(1 \, \text{g/cm}^3\).

3. **Conditions for Sinking**:
- A solid will sink in water if its relative density is greater than 1. This means that the density of the solid is greater than the density of water.
- If RD < 1, the solid will float. If RD = 1, the solid will be neutrally buoyant (neither sinking nor floating).

4. **Analyzing Options**:
- **Option 1**: Relative Density < 1: The solid will float.
- **Option 2**: Relative Density = 1: The solid will neither sink nor float; it will be at the water level.
- **Option 3**: Relative Density > 1: The solid will sink.
- **Option 4**: Infinite Relative Density: This is a theoretical case and does not apply practically; it implies the solid would neither float nor sink.

5. **Conclusion**:
- The correct condition for a solid to sink in water is when its relative density is greater than 1. Therefore, the answer to the question is that any solid will sink in water if its relative density is greater than 1.

### Final Answer:
Any solid will sink in water if its relative density is **greater than 1**.

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