Water having density ‘⍴’ is flowing (steadily) downwards in the given tube. What is the relation between PA & PB?

The fluid speed will be less at B according to the equation of continuity (Av = const).An intuitive way to think about this problem is that pressure at B has to be greater than that at A as the pressure difference not only has to balance gravity (which is trying to increase its velocity), but also decrease fluid speed. Another way is to use the Bernoulli equation.PA + ρgh + 1/2 ρvA2 = PB + 1/2ρ vB2. AAvA = ABvBPB – PA = ρgh + 1/2 ρvA2 – 1/2 ρvB2—————–(1)vB < vA(because AB > AA)Therefore we can say that R.H.S of equation (1) is positivewhich in turn shows that PB – PA > 0.