posted by Abby .
In black-and-white photography, a photon energy of about 4.00 x 10-19 J is needed to bring
about the changes in the silver compounds used in the film. (a) What is the frequency of the
light needed to bring about these changes? When you input large numbers such as those in
this problem, then input the numbers with parenthesis so as to obtain the correct answer. (b)
Explain why a red light used in a darkroom does not affect the film during developing.