如何計算水壓 ?

Use the simple equation: pressure = h.d.g
where h is the height (or depth) of water column
d is the density of water (taken to be 1000 kg/m^3)
g is the acceleration due to gravity (taken to be 10 m/s^2 for simplicity. But for more accurate calculation, you should use g = 9.81 m/s^2 )

Hence, given a depth of 200m, the pressure
= 200 x 1000 x 10 N/m^2 = 2 x 10^6 N/m^2 = 2 x 10^6 Pa

If given a pressure of 23 x 10^5 Pa
depth of water = 23 x 10^5/(1000 x 10) m = 230 m

Pressure= density x gravity x height
( you should find out the mass or volume or density first.)