{HEAD ~ The output} of the operational amplifier is proportional to {TAIL ~ the incident light} provided the intensity on each photodiode are proportional to each other 
is proportional to
{ HEAD ~ The output } of the operational amplifier is proportional to { TAIL ~ the incident light } provided the intensity on each photodiode are proportional to each other
HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH