What is transmittance in optical measurements?

Transmittance refers to the amount of light that passes through a material compared to the total light incident on that material. This concept is crucial in optical measurements, as it quantitatively describes how much light can successfully travel through a substance without being absorbed or reflected. Transmittance is typically expressed as a ratio or percentage, indicating the efficiency of a material in allowing light to pass through it. Understanding transmittance is vital in various applications, such as designing optical systems and analyzing materials in scientific research. In this context, the correct answer provides a clear definition aligned with the fundamental principles of optics.