Water flows throu

Let the wider tube be called A and the narrow tube be called B.

Given, area of cross-section of tube A,

area of cross-section of tube B,

Rate of flow through the tubes,

Let the velocity of flow at A and B be and respectively.

From the equation of continuity, we know

Similarly,

The pressure difference between the points is equal to the difference in the mercury columns. Let the pressure at A be and that at B be . Also, Let the difference in height of the mercury columns be

From the Bernoulli’s equation