During operation, an automobile exhaust gas stream has oxygen concentration of $10-20$ atm. Calculate the cell emf generated by the oxygen sensor operating at $700\backslash$deg C and using reference oxygen partial pressure of oxygen partial pressure of

$($a$)1$ppm pO$2$ and

$($b$)0\mathrm{.}21$ atm pO$2.$

Use R$=8\mathrm{.}314$ J$.$K$-1.$mol$-1$

$($Gas constant$),$ F$=96485$ C$.$mol$-1($Faraday constant$).$