Question

A coin is located at the bottom of a swimming pool of depth 1,80m, draw a ray diagram to show how the image of the coin is formed as seen by an observer in air

Answer 1

The ray diagram is shown on the figure below.

Here angles $\theta_1$ and $\theta_2$ of the input rays obey the Snell's law:

$$n_1\sin\theta_1 = n_2\sin\theta_2$$

where $n_1$ and $n_2$ are refractive indices of air and water respectively. And the same for the output rays.