If a sample absorbs 20% of light, what is the transmittance (T)?

When a sample absorbs 20% of light, it means that 20% of the incident light is not transmitted through the sample. To find the transmittance, it is important to understand that transmittance is defined as the fraction of light that passes through a sample compared to the amount of light that was incident on it.

Transmittance can be calculated by subtracting the absorbance (which is the percentage of light that is absorbed) from 100%. Given that 20% of light is absorbed, this implies that 80% of the light is transmitted through the sample. Therefore, the transmittance can be expressed as:

T = (100% - % absorbance) / 100

T = (100% - 20%) / 100

T = 80% / 100 = 0.8

This calculation confirms that the transmittance of the sample is 0.8, meaning that 80% of the incident light is transmitted. Thus, the answer provided is indeed correct.