Atank holds a 1.44-m thick layer of oil that floats on a 0.98-m thick layer of brine. both liquids are clear and do not intermix. point o is at the bottom of the tank, on a vertical axis. the indices of refraction of the oil and the brine are 1.40 and 1.52, respectively. a ray originating at o crosses the brine-oil interface at a point 0.7 m from the axis. the ray continues and emerges into the air above the oil. what is the angle that the ray in the air makes with the vertical axis