Pressure in a tapered pipe

The fluid moves faster in the narrow tube. Energy stays the same, so when it moves slower, the pressure is higher.

I have taken this from Wikipedia for quick reference.

The Bernoulli's principle states that an increase in the speed of a fluid occurs simultaneously with a decrease in pressure or a decrease in the fluid's potential energy. The simple form of Bernoulli's equation is valid for incompressible flows.

A common form of Bernoulli's equation, valid at any arbitrary point along a streamline, is:

$\frac{v^2}{2} + gh + \frac{p}{\rho} =$ constant, where

$v$ is the fluid flow speed at a point on a streamline,

$g$ is the acceleration due to gravity,

$h$ is the elevation of the point above a reference plane, with the positive z-direction pointing upward – so in the direction opposite to the gravitational acceleration,

$p$ is the pressure at the chosen point, and

$\rho$ is the density of the fluid at all points in the fluid.

As points $A$ and $B$ have the same height $h,$ we can ignore the $gh$ terms on either side. Also, from continuity equation ( $A_1v_1 = A_2v_2$ ), because the cross-sectional area at $A$ is greater, the velocity is lower. So $v_A < v_B$ . Thus it follows from Bernoulli's equation, that $\boxed{P_A > P_B}$ .

If flow is constant then

$A\times v=constant$

where $A$ is the area of the pipe's section at a point of the pipe and $v$ is the speed of the fluid at that point. Therefore near the broad end the speed is at its minimum.

According to Bernoullli's law:

$p+\delta gh+\frac{\delta v^{2}}{2}=constant$

where $p$ is the pressure of the fluid in that certain point, $\delta$ is the density of the fluid, $g$ is gravitational acceleration, $v$ is the speed of the fluid in that certain point and $h$ is the height. Since, as said before, speed is at its minimum in point A, and the pipe is level, pressure is at its maximum at point $\boxed{A}$

The reason for this is the Bernoulli effect, but to think about it another way, the fluid is moving faster at B than at A, so it must have more pressure behind it than in front of it to allow it to accelerate.

Ac to bernouli where speed is high pressure is low Also ac to eq of cont for ideal fluid, where small cross section area speed is high So at point A greater the cross section area smaller will be speed and high will be pressure

Put simply, the total energy of inflow and outflow has to be the same.

People have confused "pressure" for "velocity of flow" which is why the 14% who were forced to study Bernoulli's principle (stated in many other answers) got the correct option, A.

Irrespective of the direction of flow, because the the water has to flow faster at B due to the taper, pressure energy is less at B and kinetic energy is more.

That's it, really.

Just apply Bernouilli's theorem, pB - pA < 0