Question

How a pressure cooker reduces cooking time for food ?
A.The higher pressure inside the cooker crushes the food material.
B.Cook involves chemical changes helped by rise in temperature.
C.Heat is more evenly distributed in the cooking space.
D.Boiling point of water involved in cooking is increased.

Answer 1

Hint:In the above question it is asked what happens inside the pressure cooker which helps the food to cook faster. In a pressure cooker, the pressure inside the cooker increases which results in increase in boiling point of water

Complete answer:
As we are asked why the food cooks faster in a pressure cooker, we can apply the relationship between pressure and boiling point of water.
Let us first analyse why the pressure inside a pressure cooker is more. When we cook food, the hot air rises. In an open pot, a lot of heat as well as the moisture present in the food escapes as evaporation. But in a pressure cooker the hot air and the steam cannot escape. And hence, the pressure inside the pressure cooker increases.
As we know that pressure and boiling point are directly proportional to each other. As the pressure inside the cooker increases, the boiling point also increases. As the boiling temperature of water increases and hence, the food cooks faster.

Hence, the correct option is option D.

Note:
You may be wondering how an increase in boiling point of water helps the food to cook at a faster rate.
As boiling point can be defined as the temperature at which vapour pressure is equal to the atmospheric pressure. When the boiling point increases atmospheric pressure also increases and hence the vapour pressure takes to be the same as atmospheric pressure. Hence, water evaporating rate decreases and hence, time of cooking reduces.