What is the difference between reflectivity and reflectance? Reflectivity is the square of the magnitude of the ratio of the reflected electric field to the incident electric field at a surface boundary Reflectance is the ratio of the total reflected power to the total incident power For an infinitely thick material, reflectivity and reflectance are the same
Why is there emissivity + reflectivity + transmittance = 1? Reflectivity, Absorptivity, and Transmissivity are defined as being fractions of the original incident light So you could have 30% reflected, 10% absorbed, and then you would know 60% was transmitted since the remaining light had to go somewhere (conservation of energy), for a total of 100% which is equal to 1
Why do metals have high optical reflectivity? You are asking why metals have highly optical reflectivity Now this has too a little bit to do with why metals are often silver The same goes why we use aluminum in our mirrors When a photon interacts with an atom in the metal, three things can happen: elastic scattering, the photon keeps its energy level and phase and changes angle
electromagnetic radiation - The rule breaker, emissivity + reflectivity . . . So if the emissivity is high for infra-red that doesn't clash with the reflectivity being high for visible light This (or rather it's converse) is exactly why greenhouses heat up in visible light They have a high emissivity and low reflectivity at visible wavelengths but a low emissivity and high reflectivity at IR wavelengths
optics - Reflectivity with complex refraction indices - Physics Stack . . . As far as I can tell, the equation above gives the reflectivity as long as the norm of the index is known, that is $$ n_1=\sqrt{n_{r_1}^2+k_1^2} \\ n_2=\sqrt{n_{r_2}^2+k_2^2} $$ in the above formula for the reflectivity, I replaced the norms of the complex numbers and not the numbers themselves,obviously
UV reflective surfaces - Physics Stack Exchange In physics, the reflectivity of a surface is described by Fresnel Equations One of the parameters of this equations is the refractive index which in general depends on the wavelength of light used So surfaces that reflect visible light need not be good reflectors in another wavelength
Is metal electrical conductivity correlated with optical reflectivity? Materials with high index of refraction have higher reflectivity than materials with lower reflectivity Because index of refraction varies with the wavelength of photons and so does reflectivity Also the metallic reflectance can be related to the conductivity by the Hagens-Ruben equation where ν is the light frequency, ε0 is the vacuum