ABSTRACT
Temperature refers to the thermal state of a substance. It is the degree of ‘hotness’ of a substance and reflects its potential for heat transfer. Heat is a form of energy associated with the kinetic motion of molecules within a substance. Heat energy gets transferred from a hotter to a colder substance. Temperature measurement can be divided into non-electrical, electrical and infrared-based methods. The standard international unit of temperature measurement is the kelvin. It is based on the triple point of water, which is the temperature at which water exists in all three phases. Gas expansion thermometers is based on the volumetric expansion of a gas with temperature and the associated pressure changes that ensue due to this volume expansion. Thermocouple Consists of two different metals joined to form two separate junctions. One junction is kept at constant temperature and is known as the reference junction while the other junction acts as the temperature-measuring probe.
