Please explain these 2 questions. Thank you.

3) Note that A=CI has the form of a straight line (that is, y=aX+b ). What does the slope of the standard curve correspond to? Where does your standard curve intercept the Y axis? If the intercept deviates from zero, explain why. 4) The UV-Vis spectrum of an aqueous solution of an azo dye has an absorbance maximum of 0.528(A) at 560nm(), and was recorded on a 6.03105M solution (C) in a 0.5cm cell (I). a) Determine the extinction coefficient (560) of the dye. b) Calculate the energy (E) of a photon of 560nm light. c) Given that the dye absorbs in the range of green light, explain why the solution appears purple