Q.Which of the following is a vector quantity?

Scalar vs Vector

Before you can add, resolve or dot anything, you have to know what kind of quantity you are holding. Physical quantities split into two families: scalars and vectors. Telling them apart is the very first idea in the vectors chapter.

The distinction

A scalar has magnitude only — a single number with a unit, and nothing more. To state it fully you just say "how much."

A vector has magnitude and direction — you must say both "how much" and "which way" for it to make sense.

Everyday examples

Why the difference matters

The same situation can hide both types, and mixing them up gives wrong answers:

• Distance vs displacement. Walk $3$ km east then $3$ km west: the distance covered is $6$ km (a scalar), but the displacement is $\vec{0}$ — you ended where you started.
• Speed vs velocity. A car going round a circular track at a steady $40$ km/h has constant speed but changing velocity, because its direction keeps turning. …