A very small bulb, a rectangular block of transparent plastic, a piece of opaque cardboard, and a screen are placed as shown in the figure below. Light travels slowly through the plastic as compared to air. The room is dark and the bulb is turned on. If the block of plastic were removed, would the height of the shadow on the screen increase, decrease or remain the same? Please support your answer with a reasonably correct ray diagram.

A very small bulb, a rectangular block of transparent plastic, a piece of opaque cardboard, and a screen are placed as shown in the figure below. Light travels slowly through the plastic as compared to air. The room is dark and the bulb is turned on. If the block of plastic were removed, would the height of the shadow on the screen increase, decrease or remain the same? Please support your answer with a reasonably correct ray diagram.