Question

A pressure cooker is used at higher altitude since the atmospheric pressure at higher altitude is
A) less than $76{\text{ }}cm$ of Hg
B) more than $76{\text{ }}cm$ of Hg
C) equal to $76{\text{ }}cm$ of Hg
D) depends upon the boiling of water

Answer 1

To solve this type of question remember the boiling point, atmospheric pressure values. A liquid boils when its vapor pressure equals the atmospheric pressure keeping this in mind to choose the correct option.

Step-step answer
Pressure cooker used at higher altitude since the atmospheric pressure at higher altitude is less than 76 cm of Hg.
A liquid boils when its vapor pressure equals the atmospheric pressure.
$1atm = 76{\text{ }}cm{\text{ of Hg}}$
At higher altitude atmospheric pressure is lower than near the sea.
This causes the water to boil at lower temperature below $100$
Due to this it takes longer time for food to be cooked.
A pressure cooker prevents boiling of water at lower temperature and leads to quicker cooking of food.

Additional information pressure decreases with increasing altitude. The pressure at any level in the atmosphere may be interpreted as the total weight of the air above a unit area at any elevation. At higher elevations, there are fewer air molecules above a given surface at lower levels.

Note: Here atmospheric refers to $1atm = 76$cm of hg.
As altitude increases, the amount of a gas molecule in the air decreases and the air becomes less dense than air nearer to the sea. It is advisable to use a pressure cooker at a higher altitude for cooking food as a result food cooks quickly.