A U-tube filled with water is being used as a manometer. If one side of the manometer is attached to a low-pressure chamber, the two water levels in the manometer move by $20\,\text{cm}$. The gravitational field strength $g$ is $10\,\text{N kg}^{-1}$. The density of water is $1000\,\text{kg m}^{-3}$. By how much is the pressure in this chamber below atmospheric pressure?
- A$2000\,\text{Pa}$
- B$4000\,\text{Pa}$
- C$200\,000\,\text{Pa}$
- D$400\,000\,\text{Pa}$