Measurement of optical absorption of a solution is disturbed by the additional stray light falling at the photo-detector. For estimation of the error caused by stray light the following data could be obtained from controlled experiments.
Photo-detector output without solution and without stray light is $500\;\mu W$
Photo-detector output without solution and with stray light is $600\;\mu W$
Photo-detector output with solution and with stray light is $200\;\mu W$
The percent error in computing absorption coefficient due to stray light is
- $12.50$
- $31.66$
- $33.33$
- $94.98$