Correct Answer - Option 4 : Pyrometer
Pyrometer:
Pyrometer is a device for measuring relatively high temperatures, such as is encountered in furnaces. Most pyrometers work by measuring radiation from the body whose temperature is to be measured. Radiation devices have the advantage of not having to touch the material being measured. So the device can not be used to measure pressure.
Strain guage:
A Strain gauge (sometimes referred to as a Strain gage) is a sensor whose resistance varies with applied force; It converts force, pressure, tension, weight, etc., into a change in electrical resistance which can then be measured. When external forces are applied to a stationary object, stress and strain are the results.
LVDT:
LVDT is an acronym for Linear Variable Differential Transformer. It is a common type of electromechanical transducer that can convert the rectilinear motion of an object to which it is coupled mechanically into a corresponding electrical signal. It also uses pressure.
Pirani gauge:
The Pirani gauge consists of a metal sensor wire (usually gold plated tungsten or platinum) suspended in a tube that is connected to the system whose vacuum is to be measured. The wire is usually coiled to make the gauge more compact. The Pirani gauge measures the vacuum pressure-dependent thermal conductivity from the heated wire to the surrounding gas.
