A $10$ V DC supply is used to machine an iron plate using ECM

operation. A tungsten tool of diameter $1$ mm is used to make a slot

by scanning the tool over the workpiece with a speed of $10\frac{m}{s}.$ A

$0\mathrm{.}2MNaN{O}_3$ is used as the electrolyte, whose conductivity is

$\frac{0\mathrm{.}2}{}-cm.$ If the inter$-$electrode gap used is $300m,$ calculate the

height of the slot.