What distinguishes scalar quantities from vector quantities?

• A. Vectors have only direction
• B. Scalars can have both direction and magnitude
• C. Scalars have only magnitude
• D. Vectors are always larger than scalars

Answer: (C)

Scalar quantities are fundamentally defined by possessing only magnitude and lacking any directional component. This means that scalars are fully described by a numerical value alone. For example, temperature and mass are scalar quantities; they can be expressed with a unit (like degrees Celsius or kilograms) without the need to specify a direction.

In contrast, vector quantities possess both magnitude and direction. This is crucial because it allows vectors to provide more information about a quantity, such as velocity or force, which indicates not only how much of something there is, but also where it is applied or directed.

The third choice correctly emphasizes that scalars only have magnitude, which distinguishes them clearly from vectors, which must include both aspects for proper representation.