Question

The unit of current density is

• A. ampere (A)
• B. coulomb (C)
• C. ampere per square metre (A/m²)
• D. volt per metre (V/m)

Hint:

Current density gives us an idea of how much current is flowing through a particular area of a conductor. Its unit is A/m².

Answer 1

The Correct Option is C

Step 1: Understanding current density.
Current density is defined as the amount of current flowing per unit area. It is given by the formula: \[ J = \frac{I}{A} \] where \( J \) is the current density, \( I \) is the current, and \( A \) is the cross-sectional area. The unit of current density is thus amperes per square meter (A/m²).
Step 2: Explanation of each option.
- (A) ampere (A): Incorrect. Ampere is the unit of current, not current density.
- (B) coulomb (C): Incorrect. Coulomb is the unit of charge, not current density.
- (C) ampere per square metre (A/m²): Correct. This is the correct unit for current density.
- (D) volt per metre (V/m): Incorrect. This is the unit of electric field, not current density.
Step 3: Conclusion.
The unit of current density is amperes per square meter (A/m²).