Chapter 14, Problem 81A

Interpretation Introduction

Interpretation: A pressure cooker reduces the time needed for cooking food is to be explained.

Concept introduction: According to Gay-Lussac’s law, the pressure of an enclosed gas will increase with the increase in temperature of the gas, provided that the volume remains the same.

Answer to Problem 81A

A pressure cooker reduces the time needed for cooking because the heat builds up faster, and the temperature is better maintained under higher pressure.

Explanation of Solution

The pressure is proportional to the temperature. Pressure increases with the increase in temperature. The increased pressure in pressure cookers raises the boiling point of water. When water begins to boil under higher pressure, food will cook faster.

This implies the food takes longer to cook before the water boils. Since the temperature is better maintained and the heat is generated faster under increased pressure, the total time needed for cooking is reduced.

Conclusion

A pressure cooker reduces the time needed for cooking because the heat builds up faster, and the temperature is better maintained under higher pressure.