The size of a quantity is called:

Attitude

Longitude

Magnitude

Vector

None of these

Option (b) - Magnitude.

Explanation:

Magnitude specifies and means ""how much"" of a given quantity is present. This word is used in physics in both vectors as well as scalars i. e in quantities which specify the direction and also those which do not specify direction.

It is used to refer to the size of the particular quantity for example mass of an object is given to be 12kg then 12 is the magnitude or size of the quantity (mass) of the object. It is the numerical value of a physical quantity.

Magnitude