Question

A non-viscous liquid is flowing through a non-uniform pipe from section `A` to section `B` as shown in the figure. Cross sectional area of the pipe at `A` is less than that at `B`. Which of the following statements are correct?

A. The pressure at `A` is greater than that at `B`
B. Velocity at `A` is greater than that at `B`
C. Total energy per unit volume of the liquid is greater at `A` than at `B`
D. Axis of the pipe cannot be horizontal

Answer 1

Correct Answer - A::B::D
Here liquid is flowing form `A` to `B`. Hence `P_(A)gtP_(B)`
According to the equation of continuity,
`a_(1)v_(1)=a_(2)v_(2)`
As `a_(2)gta_(1)`, hence `v_(1)=v_(2)` As the liquid is non viscous, there is no loss of energy i.e., energy per unit volume of the liquid is the same at every point.
So option `c` is correct
Here `P_(A)gtP_(B)`, so `v_(A)gtv_(B)` and energy /volume of liquid is same at every point. So `(PE)_(A)lt(PE)_(B)`.
Hence, section `A` must be at the lower level than section `B` i.e., the pipe cannot be horizontal.