Nanoparticles are small collections of atoms that can have properties and behaviors that are very different from a bulk sample of the material. Gold and silver are two metals that are able to form nanoparticles with useful properties. One difficulty in the manufactured formation of these particles is avoiding methods that involve toxic chemicals. One potential method for producing gold nanoparticles is to use light energy to reduce gold ions, A u 3 + , to neutral gold metal, A u . The difficulty with this method lies in finding a system that can efficiently capture light energy and convert it into chemical energy. Researchers tested the ability of chloroplasts extracted from two different plant species, one an aquatic pond weed and the other spinach, to use light to create gold nanoparticles.

Question

n a second study, the researchers took spinach extract and varied the concentration of the gold ions in the solution. The solutions were then either exposed to light or kept in the dark for 30 minutes at 24 ∘ C . The data is presented in Figure 2.

In a third study, the researchers used spinach extract with 2 mM gold ions and exposed the solutions to varying intensities of light for varying time intervals at 24 ∘ C . The data is presented in Figure 3.

A Measuring the light intensity allows the researchers to control the number of nanoparticles produced. B Measuring light intensity allows an analysis of the relationship between light intensity and nanoparticle production. C Measuring light intensity is a method for setting the blank on the spectrophotometer. D Measuring light intensity is required to ensure the experiment runs safely.

Answer 1

The best interpretation of the significance of measuring light intensity in the context of the researchers' studies is option B: Measuring light intensity allows an analysis of the relationship between light intensity and nanoparticle production.

This option addresses the core purpose of varying light intensity which is to explore how it affects the production of gold nanoparticles in the solutions, providing insights into the efficiency of the light energy conversion process in generating these nanoparticles. Options A, C, and D do not directly capture the primary scientific aim behind measuring light intensity in this experimental setup.