A 100 mm long cylindrical steel rod with a 10 mm diameter is exposed on a beach for one year. The steel rod corroded over the year and experienced a weight loss of 30 g. Determine the corrosion penetration rate of the steel rod in mm/yr. The corrosion penetration rate is expressed as 4 CPR = KW/pAt Where, W is the weight loss in mg; r is exposure time in hour; Density, p-7.9 g/cc (for steel) Exposed area, 4 in cm; and K is a constant-87.6 (for CPR in mm/yr). [Marks 10]