BACHELOR OF SCIENCE (HONS) Lecture Notes - Lecture 1: Physical Quantity, Unit Vector, Electric Current
23 May 2022
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Document Summary
Different physical quantities can be classified into the following two categories: Scalar quantities are those quantities which require only the magnitude for their complete specifications. Physical quantities which can be completely specified by a number and unit, and therefore have the magnitude only, are scalars. Some physical quantities which are scalar are mass, length, time, energy, volume, density, temperature, electric charge, electric potential etc. These examples obey the algebraic law of addition. Vector quantities are those quantities which require magnitude as well as direction for their complete specifications. Vectors are physical quantities, which besides having both magnitude and direction also obey the law of geometrical addition. (the law of geometrical addition, i. e. the law of triangular addition and law of parallelogram are discussed later in this chapter). Some physical quantities, which are vectors are displacement, velocity, acceleration, force, electric intensity, magnetic intensity, magnetic moment etc. Vector quantities cannot, in general, be added in algebraically.
