Question

Three vertical tubes X, Y and Z are connected to a horizontal pipe as shown in figure. At the point of joint, the radii of pipe are 2 cm, 1 cm and 2 cm respectively. Water is flowing in this pipe. The water level in the vertical tubes will be:

• A. upto same height in X and Z.
• B. upto same height in all the three.
• C. upto same height in X and Y.
• D. upto maximum height in X.

Answer 1

Answer: (A)

upto same height in X and Z.

Since X and Z are connected to the pipe having same cross section area, so the flow of water will have the same velocity there, hence the pressure (height of water) will be same according to Bernoull's theorem. $\Rightarrow$ A is correct.
Y is connected to pipe having smaller cross section area, so the flow of water will have higher velocity there, hence the pressure (height of water) will be lesser in comparison to X and Z according to Bernoull's theorem. $\Rightarrow$ B,C, and D are incorrect.