All the articles discussed & analysed here are useful for calculating the important parameters such as solid angle subtended by the beam at the point-source, total area intercepted by the beam with a spherical surface & cone angle of equivalent beam with circular section. These formula are very useful for replacing the rectangular profile by circular profile of a beam emitted by a uniform point-source & vice versa without any change in the total radiation energy/luminous flux associated with the original beam (having either rectangular or circular profile). Thus the articles discussed & analysed here are very useful for the analysis of radiation energy & determining the intensity of (uniform) point-source in a given direction in Radiometry & for the analysis of luminous flux & luminous intensity of (uniform) point-source in a certain direction in Photometry. These are also very useful in replacing the rectangular aperture by a circular aperture & vice versa without any change in the total radiation energy/luminous flux passing through an original aperture & thus useful for the analysis & the designing of optical\beam emitting (like laser) devices based on (uniform) point-sources.