A spaceship is designed to support animal life for a multiyear voyage to the outer planets of the solar system. Plants will be grown to provide oxygen and to recycle carbon dioxide.
-Since the spaceship will be too far from the sun for photosynthesis, an artificial light source will be needed. What wavelengths of light should be used to maximize plant growth with a minimum of energy expenditure?
A) full-spectrum white light
B) green light
C) a mixture of blue and red light
D) yellow light
E) UV light

Question

Quizplus · Accepted Answer

Plants require both blue and red wavelengths of light for optimal growth, as these are the wavelengths most efficiently absorbed by chlorophyll for photosynthesis. Full-spectrum white light would require more energy expenditure as it contains wavelengths that plants do not use efficiently. Green light is not efficiently absorbed by plants and may even be actively reflected, while yellow light does not provide the necessary wavelengths for efficient photosynthesis. UV light can be damaging to both plants and animals and is not necessary for plant growth. Therefore, a mixture of blue and red light would provide the most efficient and effective form of artificial light for the plants on the spaceship.

A Spaceship Is Designed to Support Animal Life for a Multiyear