The pressure of a gas is measured using a manometer as shown in the diagram.
The mercury in the manometer is replaced with a liquid which is less dense. How does the value of h change?
A It becomes zero.
B It decreases, but not to zero.
C It stays the same.
D It increases.
Solutions: Option D
The pressure to be measured remains constant. Since P = pgh, where p is the density of the liquid used in the manometer. If a liquid of lower density is used, height h of the liquid (level difference) will be greater. The gravitational field strength g remains constant.