A transparent glass slab of thickness t (refractive index μg) is kept horizontally over a tank of water of depth h (refractive index μw). An object O is placed at the bottom of the tank and is viewed normally from air.
a. (i) With the help of a neat, labelled ray diagram, show the formation of the image of O for the observer in air.
b. (ii) Derive an expression, in symbols only, for the total apparent depth of the object as seen by the observer.
c. (iii) Using your expression, calculate the apparent depth when t=1.0cm, h=80cm, μg=1.5 and μw=1.33. Give your answer correct to two significant figures.