What do mean by intensity in terms of physics?
In physics, intensity is a measure of the time-averaged energy flux. The word “intensity” here is not synonymous with “strength”, “amplitude”, or “level”, as it sometimes is in colloquial speech. For example, “the intensity of pressure” is meaningless, since the parameters of those variables do not match. To find the intensity, take the energy density (that is, the energy per unit volume) and multiply it by the velocity at which the energy is moving. The resulting vector has the units of power divided by area (i.e. watt/m²). It is possible to define the intensity of the water coming from a garden sprinkler, but intensity is used most frequently with waves (i.e. sound or light). In photometry and radiometry intensity has a different meaning: it is the luminous or radiant power per unit solid angle. This can cause confusion in optics, where intensity can mean any of radiant intensity, luminous intensity or irradiance, depending on the background of the person using the term. Radiance is
