Florida Drinking Water Operator "B" Practice Test

Which instrument is used to measure the color intensity of a chemical solution?

1. pH meter

2. Colorimeter

3. Spectrophotometer

4. Refractometer

The correct answer is: Spectrophotometer

The spectrophotometer is the instrument used to measure the color intensity of a chemical solution because it works by passing light through the solution and measuring the amount of light absorbed at specific wavelengths. This absorption is directly related to the concentration of colored compounds in the solution, and by using a spectrophotometer, operators can quantify how intense the color is based on the transmitted and absorbed light. In water treatment, understanding the color of water is essential as it can indicate the presence of organic materials, sediments, or other impurities. The spectrophotometer's ability to measure light absorption allows operators to detect and analyze even slight changes in the water's color, making it a critical tool for assessing water quality. While a colorimeter is also used to measure color intensity, it typically operates over a narrower range of wavelengths and may not provide the same level of detail as a spectrophotometer in complex solutions. A pH meter is used for measuring acidity or alkalinity and does not assess color. A refractometer measures the index of refraction of a liquid and is primarily used for assessing concentrations of dissolved substances, but it does not provide information on color intensity. The choice of a spectrophotometer in this context is due to its precision and