An object is viewed through a glass prism with its vertex pointing upwards. Draw a ray diagram to show the formation of its image seen by the observer.
Let two rays OA and OL from a source 0 are incident on the prism. They are refracted along AB and LM from the first face of the prism. These two rays again refract from the second face of the prism emerge out along BC and MN respectively such that they appear to come from I. Thus observer sees the object O raised to the position I.