Which of the following is called current density:

Options

A. `(I)/(A)`
B. `(I^(2))/(A)`
C. `(A)/(I)`
D. `(I^(3))/(A)`

Explanation

To solve the question regarding which of the following is called current density, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Concept of Current Density**:
- Current density is defined as the amount of electric current flowing per unit area of a cross-section. It gives us an idea of how concentrated the current is in a given area.

2. **Identify the Formula for Current Density**:
- The formula for current density (J) is given by:
\[ J = \frac{I}{A} \]
where:
- \( J \) = current density (measured in amperes per square meter, A/m²)
- \( I \) = current flowing through the conductor (measured in amperes, A)
- \( A \) = cross-sectional area through which the current flows (measured in square meters, m²)

3. **Determine the Nature of Current Density**:
- Current density is a vector quantity. This means it has both magnitude and direction. The direction of the current density vector is the same as the direction of the flow of positive charge.

4. **Conclusion**:
- Based on the definition and formula, we can conclude that the term that represents current density is indeed \( J \), which is defined as the current per unit area.

### Final Answer:
- The correct answer is that current density is represented by \( J = \frac{I}{A} \), and it is measured in amperes per square meter (A/m²).