For the manometer set$-$up shown in Fig. P$2\mathrm{.}7,$ find the difference in pressure $($p$\_\{$A$\}-$ p$\_\{$B$\})$ when

$($a$)$ H$\_\{1\}=0\mathrm{.}3$ m and H$\_\{2\}=0\mathrm{.}05$m

$($b$)$ H$\_\{1\}=0\mathrm{.}05$m and H$\_\{2\}=0\mathrm{.}30$m

Take gamma$\_\{$w$\}=9\mathrm{.}79$kN $/($m $^2)$