What is the S.I. unit of density ?

Answer

To determine the S.I. unit of density, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Definition of Density**:
Density is defined as the mass of a substance per unit volume.

\[ \text{Density} = \frac{\text{Mass}}{\text{Volume}} \]

2. **Identify the S.I. Units for Mass and Volume**:
- The S.I. unit of mass is **kilogram (kg)**.
- The S.I. unit of volume is **cubic meter (m³)**.

3. **Substitute the S.I. Units into the Density Formula**:
Using the formula for density, we can substitute the S.I. units for mass and volume:

\[ \text{Density} = \frac{\text{Mass (kg)}}{\text{Volume (m}^3\text{)}} \]

4. **Express the S.I. Unit of Density**:
Therefore, the S.I. unit of density can be expressed as:

\[ \text{Density} = \frac{\text{kg}}{\text{m}^3} = \text{kg/m}^3 \]

### Final Answer:
The S.I. unit of density is **kilogram per cubic meter (kg/m³)**.

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