You might have seen sunglasses that change to a color whenexposed to light, while revert to transpaparency when the light isblocked or dimmed. Thematerical used to make the glasses is calledphotochromic material that has light sensitive components inside.The technology is similar to that used to make a photographicfilm.
(a) Explain, using necessary chemical formula, the workingprinciple of photochromic sunglasses.
(b) The color of the photochromic sunglasses is reversible,however, the image on a photographic film once exposed anddeveloped, is fixed and becomes irreversible. Why?
