Why does a green leaf appear green in daylight but dark in red light?

Why does a green leaf appear green in daylight but dark in red light?

PROF WAQAR HUSSAIN

                                    GREEN LEAF             DARK LEAF

                In sunlight or white light the green leaf absorbs all constituents light colours of white except green. It means the leaf absorbs all wavelengths of colours i.e. violet, indigo, blue, yellow, orange, red but not green. Since the green light alone is reflected thus leaf appears green. Under the red light all colours including the green are absorbed in the red colour. Hence the leaf appears as dark.