Question

Consider the barometer shown in figure. If a small hole is made at a point P in the barometer tube, will the mercury come out from this hole?

Answer 1

Two pressures are acting upon point P:
(1) Pressure due to mercury level above point P equals to P₁ (say)
(2) Atmospheric pressure = P₀ (inwards)
And,
P₀ > P₁
As the inward pressure is more, the mercury will not come out of the hole.