Based on the work of Engelmann, a plot of photosynthetic activity versus wavelength of light is referred to as __________.

• A. an effective spectrum
• B. an absorption spectrum
• C. an electromagnetic spectrum
• D. a visible light spectrum
• E. an action spectrum

Answer: (E)

Verified step by step guidance

1. Understand the concept of photosynthetic activity: Photosynthesis is the process by which plants, algae, and some bacteria convert light energy into chemical energy. Photosynthetic activity refers to the rate at which this process occurs, often measured by the amount of oxygen produced or carbon dioxide consumed.
2. Learn about Engelmann's experiment: The work of Theodor Engelmann involved using a prism to split light into its component wavelengths and then observing the effect of these different wavelengths on photosynthetic activity in algae. He used oxygen-sensitive bacteria to identify areas of high photosynthetic activity.
3. Define the term 'action spectrum': An action spectrum is a graph that shows the rate of physiological activity (such as photosynthesis) plotted against different wavelengths of light. It indicates which wavelengths are most effective in driving a particular biological process.
4. Differentiate between the given options: An absorption spectrum shows the wavelengths of light absorbed by pigments, while an electromagnetic spectrum encompasses all types of electromagnetic radiation. A visible light spectrum refers to the range of light visible to the human eye. An effective spectrum is not a standard term in this context.
5. Conclude with the correct term: Based on Engelmann's work, the plot of photosynthetic activity versus wavelength of light is referred to as an 'action spectrum,' as it specifically relates to the effectiveness of different wavelengths in driving photosynthesis.