a) Calculate the penetration rate in m/yr equivalent to 1A/cm2 for an alloy with the composition shown in Figure 3. Given that density and atomic weight for each element respectively: Iron=7.9 g/ cm3,55.8g/mol; Chromium =7.1g/cm3,51.9g/mol; Magnesium =1.7g/cm3,24.3g/mol; Nickel =8.9g/cm3,58.6g/mol. (6 marks) b) Construct a Tafel plot for a reaction of Plumbum (Pb) in acidic solution complete with labelled axis (symbol and unit), slope, extrapolation line, example of lcon&Econ values assigned on the diagram. Write the chemical reaction involved nearby the slope. (6 marks) c) Describe the phenomenon of concentration polarization. (4 marks) d) State a comparison between conventional and modern techniques in corrosion measurement. (4 marks)