numerical value of magnitude of a physical quantity is
Physical quantity A physical quantity is a physical property of a phenomenon, body, or substance, that can be quantified by measurement or we can say that quantities which we come across during our scientific studies are called as the physical quantities.[1] A physical quantity can be expressed as the combination of a magnitude expressed by a number – usually a real number – and a unit:   n u  {\textstyle nu}  where   n  {\textstyle n}  is the magnitude and   u  {\textstyle u}  is the unit. For example, 6973167492749999999♠1.6749275×10−27 kg (the mass of the neutron), or 7008299792458000000♠299792458 metres per second (the speed of light). The same physical quantity   x  {\textstyle x}  can be represented equivalently in many unit systems, i.e.   x = n 1  u 1  = n 2  u 2   {\textstyle x=n_{1}u_{1}=n_{2}u_{2}} .