A small coin is fixed at the center of the base of an empty of cylindrical stell container having radius R = 1 m and height d = 4 m . At time t = 0 s, the container starts gettting filled with water at a flowrate of `Q= 0.1 m^3//s` without disturbing the coin . Find the approximate time when the coin will first be seen by teh observer "O" from the height of H= 5.75 m above and L = 1.5 m radially away from the coin as shown in the figure. Refractive index of water in n = 1.33
