Q$.$ No$.1$: For an ultrasonic level meter $($transmitter installed at bottom of vessel$),$ the transmitter responds with the echo of sound wave after $4$ min $.$ The transmitter itself takes $0\mathrm{.}5$ min to respond. The speed of sound in process fluid is $\backslash (15\backslash$mathrm$\{$~cm$\}/\backslash$mathrm$\{$s$\}\backslash ).$ Determine the level$($height$)$ of liquid in the vessel.