Consider the two statements A and B
A: Neutral temperature does not depend on cold junction temperature.
B: Inversion temperature does not depend on cold junction temperature
Consider the two statements A and B
A: Neutral temperature does not depend on cold junction temperature.
B: Inversion temperature does not depend on cold junction temperature
The correct option is B A is correct but B is wrong
Statement A is correct : Neutral temperature does not depend on cold junction temperature.
In a thermocouple an increase in the hot junction causes an increase in the thermo emf and reaches a maximum value called the neutral temperature(θn). This neutral temperature is independent of the temperature of the cold junction. For example θn for Cu-Fe thermocouple is 270∘C.
Statement B is incorrect : Inversion temperature does not depend on cold junction temperature.After the thermocouple reaches the neutral temperature on further increasing the temperature of the hot junction , there is decrease in the e.m.f and becomes zero. A further increase would reverse the direction of direction and this temperature is called the temperature of inversion. The relationship between emf and temperature is given by the relation:
E=αt+12βt2 ---- ( 1 ) when the cold junction is at 0∘C
E=α(t−t0)+12βt2 ----(2) when the cold junction is at 0∘C
When the temperature at cold junction is increased, the neutral temperature is the same while the inversion temperature ti(=2tn−t0) decreases.
Statement A is correct : Neutral temperature does not depend on cold junction temperature.
In a thermocouple an increase in the hot junction causes an increase in the thermo emf and reaches a maximum value called the neutral temperature(θn). This neutral temperature is independent of the temperature of the cold junction. For example θn for Cu-Fe thermocouple is 270∘C.
Statement B is incorrect : Inversion temperature does not depend on cold junction temperature.After the thermocouple reaches the neutral temperature on further increasing the temperature of the hot junction , there is decrease in the e.m.f and becomes zero. A further increase would reverse the direction of direction and this temperature is called the temperature of inversion. The relationship between emf and temperature is given by the relation:
E=αt+12βt2 ---- ( 1 ) when the cold junction is at 0∘C
E=α(t−t0)+12βt2 ----(2) when the cold junction is at 0∘C
When the temperature at cold junction is increased, the neutral temperature is the same while the inversion temperature ti(=2tn−t0) decreases.
