In an experiment to measure the quantum yield of a photochemical reaction, the absorbing substance was exposed to 490nm light from a 100w source for 45 min. the intensity of the transmitted light was 40% of the intensity of the incident light. as a result of irradiation, 0.344 mol of the absorbing substance decomposed. determine the quantum yield. (hint (1) calculate the total energy delivered to the source, (2) calculate the energy delivered by 490nm radiation per photon, (3) then calculate the number of photons, (4) then calculate the number of photons absorbed in mol and finally (5) you can calculate the quantum yield. the quantum yield is:

a) .89

b) .67

c) .52

d) .42