What is a major component of a turbidimeter?

A turbidimeter is an instrument specifically designed to measure the turbidity in liquids, which is an indication of the presence of suspended solids that can scatter light. The major component of a turbidimeter is the light source, which emits light that passes through the sample. The amount of light that is scattered by the particles in the liquid is then detected by a sensor, typically located at a certain angle from the light source. The degree of light scattering correlates with the concentration of suspended particles, allowing for the quantification of turbidity.

While measuring cups are necessary for holding the sample, and filtration systems and automated samplers may be involved in the broader context of water treatment processes, they do not define the crucial measurement capability of a turbidimeter. The light source is central to the function of the instrument and is responsible for enabling the turbidity measurement, making it the correct answer.