Question

Which one of the following is not a scalar quantity?
a.Temperature
b.Density
c.Mass
d.Weight

Answer 1

Hint:- Before solving this question, we need to be familiar with the following terms:-
SCALAR QUANTITY: Scalars are the quantities that are fully described by numerical value alone. For example, distance, speed, time, temperature, etc are scalar quantities because they are associated with only magnitude.
VECTOR QUANTITY: Vectors are quantities that are described by both numerical value (magnitude) and a direction. For example, displacement, velocity, acceleration etc are vector quantities because they are associated with magnitude as well as direction.

Complete step by step answer:
a).Temperature: Temperature is the measure of the hotness or coldness of an object or substance. It is a scalar quantity because it does not include direction.
b).Density: Density is how much space an object or substance takes up in relation to the amount of matter in that object or substance. In other words, density is the amount of mass per unit of volume. If an object is heavy and compact, it has a high density. Density is a scalar quantity because it gives no information about direction. Another reason for that is, density is equal to mass divided by volume and both mass and volume are scalar quantities, so density must also be a scalar quantity.
c).Mass: A measure of the amount of matter constituting a physical body is called the mass of that body. And as mentioned above, mass is a scalar quantity.
d).Weight: The weight of an object is defined as the force of gravity acting on the object. It is a vector quantity because weight is mass times the acceleration due to gravity, i.e.,
Weight \[=mass\times acceleration\] due to Gravity and because acceleration due to gravity is a vector quantity, therefore, weight also happens to be a vector quantity.
So, the answer is (d) Weight.

Note:- One must be able to differentiate properly between Scalar and Vector quantities, as defined in the hint.
Lacking the information about what vectors are and what scalars are the student might commit a mistake while solving the question.