The polarization resistance of a $90Cu-10Ni$ alloy in flowing seawater containing $6\mathrm{.}6m\frac{g}{L}$ oxygen was

observed to be $R_P=2\mathrm{.}7k$ after an immersion time of $40h.$ The sample area was $11\mathrm{.}05c{m}^2.$ The

cathodic process was under $O_2$ diffusion control, and the anodic process was under activation control

with an anodic Tafel slope of $+0\mathrm{.}070V.$

$($a$)$ What was the corrosion rate of the alloy in microamperes per square centimeter at $40h$ immersion?

$[3$ pts$]$

$($b$)$ What was the corresponding weight loss in grams per square meter day assuming that corrosion of

the alloy occurs mainly as: $CuC{u}^{2+}+2e^{-}.[3$ pts$]$