Question

If a hole is made in the Torricelli's vacuum portion of a barometer, then the mercury

• A. level will fall in the stem and the mercury will collect in the reservoir
• B. level will oscillate between reservoir level and original level of the mercury in the stem
• C. will spill through the hole made
• D. level in the stem will remain at the same level indicating atmospheric pressure

Answer 1

The correct option is A level will fall in the stem and the mercury will collect in the reservoir

Barometer measures the atmospheric pressure
${\rho }_{atm}-{\rho }_{Hg}gh$


If there is a hole in the vacuum portion, then there will be zero pressure difference at top and bottom of the stem. The mercury in the stem will show zero reading i.e. it will fall and get collected in the reservoir.