Which of the following methods is an example of direct measurement of pressure? 

Explanation:

Bourdon Tube

• A Bourdon tube is a mechanical device used for measuring pressure.
• It consists of a curved, hollow tube that straightens out when exposed to internal pressure.
• This deformation is proportional to the pressure applied and can be measured and displayed using a pointer mechanism.
• The Bourdon tube operates on the principle of elastic deformation.
• As pressure is applied to the inside of the curved tube, it tends to straighten out.
• This motion is transferred to a pointer through a series of linkages and gears, allowing for a precise reading of the pressure.

Advantages:

• Simple and robust design, making it durable and reliable.
• Capable of measuring a wide range of pressures, from very low to very high.
• No external power source is required for operation, as it is a purely mechanical device.

Disadvantages:

• Mechanical parts can wear out over time, leading to potential inaccuracies.
• Not suitable for dynamic or rapidly changing pressures due to mechanical inertia.

Applications: Bourdon tubes are widely used in various industrial and commercial applications, such as in pressure gauges for boilers, air compressors, and hydraulic systems.