you look down at a coin that lies at the bottom of a pool of liquid of depth d and index of refraction n (fig. 34.33). because you view with two eyes, which intercept different rays of light from the coin, you perceive the coin to be where extensions of the intercepted rays cross, at depth da instead of d. assuming that the intercepted rays in fig. 34.33 are close to a vertical axis through the coin, show that da da = d=n.
