A ripe banana will appear black when illuminated by blue light.
Work Step by Step
Blue is the complementary color to yellow. Blue + yellow = white. Under normal illumination, the banana absorbs the complementary color to yellow (which is blue), reflecting yellow light. The banana appears black when illuminated by blue light, because the fruit absorbs that light, and there is no "yellow" light to reflect. This is discussed on pages 505-506 and 509-511.