Question

In the figure shown below, the liquid taken in the siphon is water. Find the pressure difference ($P_B-P_A$) between the points $A$ and $B$.

• A. $400{\text{N/m}}^2$
• B. $3000{\text{N/m}}^2$
• C. $1000{\text{N/m}}^2$
• D. Zero

Answer 1

The correct option is D Zero

As shown in the figure below


Points A and B are in direct exposure to the atmosphere.
Therefore, pressure on points A and B will be equal to atmospheric pressure $p_0$ (say).
Hence, we can write
Pressure at point A as $P_A=P_0$
Pressure at point B as $P_B=P_0$
$\therefore$ The pressure difference between points A and B,
$=P_B-P_A=0$