The Nature of Scalar and Vector Quantities
In physics, quantities are categorized into scalars and vectors based on their characteristics. Understanding these concepts is crucial for students preparing for competitive exams like UPSC.

Definition of Scalar Quantity
- Scalar quantities are defined as those that have only magnitude and no direction.
- Examples include temperature, mass, and electric current.

Examples of Scalar Quantities
- **Electric Current**:
- Measured in amperes (A), it represents the flow of electric charge.
- It has a magnitude (e.g., 5 A) but does not have a direction associated with it.
- **Displacement**:
- A vector quantity that represents the change in position of an object.
- It has both magnitude (how far) and direction (where to).
- **Velocity**:
- Also a vector quantity, representing the rate of change of displacement.
- It indicates both speed (magnitude) and direction (e.g., 60 km/h to the north).

Conclusion
In summary, among the quantities listed—electric current, displacement, and velocity—only electric current is a scalar quantity. Displacement and velocity are vector quantities due to their dependence on direction. Understanding these classifications is essential for mastering physics concepts and excelling in examinations.