GATE 2022 Mechanical Engineering PYQ

Question

Electrochemical machining operations are performed with tungsten as the tool, and copper and aluminum as two different workpiece materials. Properties of copper and aluminum are given in the table below.

$$ \begin{array}{|c|c|c|c|} \hline ext { Material } & \begin{array}{l} ext { Atomic mass } \ ext { (amu) } \end{array} & ext { Valency } & ext { Density }\left(\mathrm{g} / \mathrm{cm}^3 ight) \ \hline ext { Copper } & 63 & 2 & 9 \ \hline ext { Aluminum } & 27 & 3 & 2.7 \ \hline \end{array} $$

Ignore overpotentials, and assume that current efficiency is 100% for both the
workpiece materials. Under identical conditions, if the material removal rate (MRR) of copper is 100 mg/s, the MRR of aluminum will be ________________ mg/s (round-off to two decimal places).