Consider a barometer tube filled with mercury as shown in the adjoining figure.
If a hole is made at a point Q as shown in the figure, will mercury come out from this hole? Given reasons

Explanation

The pressure at the level of surface of liquid exposed to the atmosphere is equal to atmospheric pressure, `P_("atm").` Since point Q is located above this level, its pressure will be less than atmospheric pressure. So, the pressure inside is less than the pressure outside, which is equal to `P_("atm")` and hence, mercury will not come out.