a) Using a basic model briefly describe the principle components of an Atomic Absorption spectrophotometer (AAS). (4 marks) b) An analyst at Kenya Bureau of Standards (KEBS) was evaluating the levels of iron in water. The absorbance of the water samples and standards at 248.3 nm was as follows. Concentration mg/L Absorbance 0 0 1 16.6 2 37.8 3 53.2 4 68.7 5 95.2 Sample 1 45.6 Sample 2 102.7 i. Determine the iron concentration (mg/L) in each of the samples. (8 marks) ii. Comment on the value of sample 2 (2 marks)