<b>Significance of Area of Obscuration and Derivation of General Expression by Method of Integration</b> In a number of Engineering applications, there are certain governing variables that bear the potential to possess a major part of the control towards the success of the process. Some of these variables may be independent while others are dependent on each other is some or the other manner. In applications involving metered quantity of fluid flow, radiation heat transfer and so on, one of such governing variables is the flow rate. Flow rate may refer to that of any fluid or radiation or solids in certain cases. As flow rate depends on the area of opening that is available for flow, it is customary to either determine the area of opening or that of obscuration. In this paper, initially the physical significance of area of obscuration in applications related to fluid flow, radiation heat transfer, packaging applications and photo sensors shall be elaborated to establish a premise for the later derived general expression for determination of the area of obscuration for a combination of two circles with different radii, with one placed at any arbitrary point in space. This general expression shall be deemed to be applicable for provided certain necessary condition is met with respect the relation between the radii of the two circles and the distance between their centres. The derived general formula shall be verified towards the end to confirm the validity for any arbitrary case. Obscuration, area, integration, definite, modulus 281-283 Issue-1 Volume-5 Gourav Vivek Kulkarni