A pressure cooker is a sealed pot with a valve that controls the steam pressure inside, and as the pot heats, the liquid inside forms steam that raises the pressure in the pot.
We know that the boiling point of water decreases with a decrease in pressure and increases with an increase in pressure. Food cooks faster in a pressure cooker. Its because the pressure increases inside the cooker, which also increases the boiling point of water. So, more heat is required to reach the boiling point and is sufficient to cook food in a reduced time.
