_________ is used for measuring vacuum.

SOLUTION

Explanation:

Pirani gauge

Pirani gauge is used for measuring vacuum (very low pressures).

The circuit diagram of measuring pressure is as shown:

Features of Pirani Gauge:

• Useful for pressure measurement ranging from 10-1 to 10-3 mm of Hg
• It is rugged in construction
• Less costly
• Usually more accurate than thermocouple gauges

LVDT (Linear Variable Differential Transformer):

• LVDT (Linear Variable Differential Transformer) is to convert the rectangular movement of an object to the equivalent electrical signal.
• The working principle of the linear variable differential transformer or LVDT working theory is mutual induction; The dislocation is nonelectrical energy that is changed into electrical energy.​​

Rotameter

• Rotameter is a constant pressure drop variable area flowmeter.
• It measures the flow rate of liquid or gas.
• As area changes, there will be a change in the Volumetric flow rate.
• No electricity is required.

The construction is as shown:

• Anemometer is a device that is used to measure wind speed in the atmosphere.
• It is commonly used at weather stations.