Inverse Square Law (ISL) is the basic principle of radiotherapy to achieve patient safety and effective delivery of doses. But the practical education of students on this law through practical ionizing radiation is very risky and very costly. In this project, we came up with a safe educational alternative, which is an optical analogy. The circuit is made up of a high intensity LED that is the source, four Light-Dependent Resistors (LDRs) that are the detectors and which are controlled by an Arduino Nano microcontroller. A laser sensor of VL53L1X was incorporated to make sure the distance is accurately measured. Several different distances were sampled in order to study the correlation between light intensity and distance and a graph of light intensity (I) against 1/r 2 was drawn. The data were quite close to the theoretical curve; e.g. the moving of the distance between 19.0 cm to 21.8 cm, which led to the decrease of the light intensity to about 30-70 percent. The device is therefore a low-cost educational instrument which enables medical physics students to experimentally confirm the inverse square law without being subjected to ionizing radiations.