Spectrophotometer is an instrument that measures the amount of light a substance absorbs or transmits at specific wavelengths to analyze its properties. It works by passing a beam of light through a sample and detecting how much light is absorbed or reflected, allowing for both the identification (qualitative) and quantification (quantitative) of a substance. This makes it a vital tool for tasks like color analysis, chemical composition analysis, and quality control across many industries, from pharmaceuticals to manufacturing.