Question

A manometer is an instrument used for measuring the pressure acting on a column of fluid, which consists of a U-shaped tube of liquid in which the difference in pressures acting in the two arms of the tube causes the liquid to reach different heights in the two arms. Which of the following is NOT a limitation of the manometer?

Difficulty in construction

Need for levelling

No over-range protection

Large and bulky size

Answer ( Option A)

Difficulty in construction

Solution

Difficulty in construction:

• Manometers are relatively simple devices and their construction is not particularly complex. They typically consist of a U-shaped tube filled with a suitable fluid, making them much easier to construct compared to many other pressure-measuring devices.

Need for leveling:

• Manometers must be perfectly level to obtain accurate measurements.

• This is because the measurement is based on the difference in height of the liquid in the two arms of the manometer, and any tilt in the apparatus can skew this difference, leading to inaccurate measurements.

No over-range protection:

• Over-range occurs when the pressure applied to the manometer exceeds its measurement range.

• Manometers don't have built-in protections against this, and a significant over-range can cause the liquid within the manometer to overflow, leading to faulty readings or damage to the manometer.

Large and bulky size:

• Compared to other pressure measuring devices, such as electronic pressure transducers, manometers can be bulky and take up more space because of the U- shaped tube design.

• Furthermore, the need to visually read the liquid column height can also necessitate a certain minimum size for the manometer.

• These properties can limit their use in locations where space is a constraint.