Question

What happens to the height of barometer when atmospheric pressure drops?
$h=$ Height of liquid in barometer.

• A. $h$ increases.
• B. $h$ decreases.
• C. $h$ does not change.
• D. $h$ becomes zero.

Answer 1

The correct option is B $h$ decreases.

The liquid pressure of the barometer column balances the atmospheric pressure, $P_{atm}$ of the barometer.
$P_{atm}=\rho gh$
where
$P_{atm}=$ Atmospheric pressure,
$\rho =$Density of the liquid,
$g=$ Gravitational acceleration,
$h=$ Height of liquid in the column.

From the above formula we can conclude that, if atmospheric pressure drops then height of liquid $\left(h\right)$ drops as well.