Question

will the colour of red flowers change when viewed in green light and why ?

Answer 1

colour of flower will not change because photosynthesis will not take place if we provide green lights to the plants ( e.g flowers ) , trees .

Answer 2

As the red colour is reflected we see it red . Now if you use green light to see the flower then the flower will absorb it and nothing will be reflected . We perceive colour of any object because that object reflect the light wave length of its colour only . And rest of the light are absorbed .