Photographic plates are coated with

ANS:B - silver halide

Silver halide refers to a class of chemical compounds composed of silver combined with one of the halogens, such as chlorine (Cl), bromine (Br), or iodine (I). The most common silver halides used in photography are silver chloride (AgCl), silver bromide (AgBr), and silver iodide (AgI). These compounds are light-sensitive, meaning they react when exposed to light. In traditional photographic processes, silver halide crystals are dispersed in a gelatin emulsion and coated onto a substrate, such as a photographic plate or film. When light strikes the silver halide crystals during exposure, a chemical reaction occurs, resulting in the formation of tiny particles of metallic silver. This forms the latent image, which is later developed into a visible image during the photographic development process. Silver halides are integral to the sensitivity of photographic materials to light, allowing them to capture and record images. Different types of silver halides have varying degrees of sensitivity to different wavelengths of light, which influences their use in various photographic applications.