The lower end of a capillary tube is dipped into water and it is observed that the water in capillary tube rises by 7.5 cm. Find the radius of the capillary tube used, if surface tension of water is 7.5 $$\times$$ 10$$^{-2}$$ Nm$$^{-1}$$. Angle of contact between water and glass is 0$$\Upsilon$$ and acceleration due to gravity is 10 ms$$^{-2}$$.

An ideal liquid flows through a horizontal tube of variable diameter. The pressure is lowest where the