Question

In a pressure cooker, food gets cooked quickly because

• A. the cooker doesn't absorb any heat.
• B. it has a safety valve.
• C. boiling point of water rises due to increased pressure.
• D. cooker does not let the energy escape and food gets cooked quickly.

Answer 1

Answer: (C)

boiling point of water rises due to increased pressure.

Boiling point of water rises due to increased pressure.

If the pressure on the water is increased, the molecules leaving the liquid have to build up a pressure equal to the pressure acting upon the water. (It is more difficult for molecules to enter the vapour phase). More energy has to be added to the water and its vapour, therefore the temperature has to be higher. More energy can be transferred at higher temperature. Hence food will get cooked early.