Determination of the refractive index of water and glass using smartphone cameras by estimating the apparent depth of an object

Abstract: A smartphone camera can be used for measuring the width and distance of an object by taking its photograph. The focal length of the camera lens can be determined very accurately by finding the image width of an object on the camera sensor to micron level accuracy. The level of accuracy achieved with the help of camera sensors, allows us to determine the refractive index of water upto four significant digits by finding the apparent depth of an object immersed in it. We have also measured the refractive index of glass by the same method, using three glass slides of different thicknesses, the smallest being 1.2 mm.