The light-sensitive substance in black-and-white photo-graphic film is AgBr. Photons pro...

The light-sensitive substance in black-and-white photo-graphic film is AgBr. Photons provide the energy necessary to transfer an electron from Br- to Ag+ to produce elemental and thereby darken the film. (a) If a minimum energy of is needed for this process, what is the minimum energy needed from each photon? (b) Calculate the wavelength of the light necessary to provide photons of this energy. (c) Explain why this film can be handled in a darkroom under red light.