Why in the News?

Pressure is an indispensable part of life, often unnoticed but always present.
- It’s the interaction of microscopic particles with the macroscopic world, creating phenomena like air pressure.

What is Pressure?

Pressure is defined as the force exerted per unit area on a surface.
For example, an apple weighing 100 g exerts a force of about 1 newton (N) on your hand and a pressure of approximately 500 Pa.
Atmospheric pressure is around 100,000 Pa, equivalent to the pressure exerted by about 200 apples on your hand.

Blood pressure, measured in mm of mercury (mmHg), is an example of pressure in a different context.
Blood pressure is measured using a sphygmomanometer, which balances the pressure in an arm cuff with the pressure of the blood in the arteries.
The readings, such as 120/80 mmHg, represent the pressure during heartbeats (systolic) and between beats (diastolic).
Mercury, being 15 times heavier than water, allows for portable blood-pressure machines.

The whistle of a pressure cooker is a direct result of the increased pressure cooking the food efficiently.
The pressure cooker exemplifies the practical application of pressure in cooking, making it an indispensable kitchen tool.

[2021] In a pressure cooker, the temperature at which the food is cooked depends mainly upon which of the following?

1. Area of the hole in the lid

2. Temperature of the flame

3. Weight of the lid

Select the correct answer using the code given below.

(a) 1 and 2 only

(b) 2 and 3 only

(d) 1, 2 and 3