Final answer:
The fraction of incident light that a body reflects is known as reflectance. It is the ratio of the intensity of the reflected wave to the incident wave and is distinct from absorption coefficient, refractive index, and transmittance.
Step-by-step explanation:
The fraction of incident light that a body reflects is known as reflectance. The intensity reflection coefficient, which can be represented as 'a', is the ratio of the intensity of the reflected wave to the intensity of the incident (transmitted) wave. This value can be utilized to determine the amount of light a surface will reflect and is an important property in various fields such as optics and material science. Reflectance is different from the absorption coefficient, which measures how much light is absorbed by a material, and the refractive index, which describes how much light bends when it passes from one medium to another. Additionally, reflectance is not the same as transmittance, which is the fraction of light that passes through a material.
Check Your Understanding - Absorptive surfaces more closely model a perfect blackbody because they absorb most of the incident light, whereas reflective surfaces tend to reflect it. The term for the minimum angle at which a light ray is reflected back into a material and cannot pass into the surrounding medium is the critical angle. Total internal reflection occurs when the incident angle is greater than the critical angle, a phenomenon exploited in technologies such as fiber optics and endoscopes.
The fraction of incident light that a body reflects is known as reflectance. Reflectance is a measure of how much of the light that hits an object is reflected back.
For example, if a body reflects 50% of the incident light, the reflectance would be 0.5. Reflectance can vary depending on the material and surface properties of the object.