Thermometric property of electric resistance thermometer - Thermodynamics
Q. In electric resistance thermometer, the thermometric property is- Published on 20 Aug 15
a. electric current passing through a metal wire
b. resistance of a metal wire
c. voltage between two extreme end points of a metal wire
d. none of the above
ANSWER: resistance of a metal wire
When current passes through a metal wire, as the temperature increases the resistance increases due to vibration of molecules in metal and collision of electrons carrying current. Therefore resistance of a metal wire is taken as a thermometric property in electric resistance thermometer. A suitable wire may be used for measuring temperature and the setup is arranged in a Wheatstone bridge circuit. Usually platinum wire is used as it can measure temperature to a high degree of accuracy and sensitivity. Platinum makes electric resistance thermometer suitable for the calibration of other thermometers.