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 maximise 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) UV light

Question

Quizplus · Accepted Answer

The wavelengths of blue (400-500 nm) and red (600-700 nm) are the most efficient in promoting plant growth through photosynthesis. Blue light activates chlorophyll synthesis and stomatal opening, while red light enhances photosynthesis and growth. A mixture of blue and red light is therefore the most efficient and effective choice for promoting plant growth with minimal energy expenditures.

A Spaceship Is Designed to Support Animal Life for a Multiyear