Example$1$

A copper$-$constantan thermocouple was found to have linear calibration between $0C$ and $400C$ with emf at maximum temperature $($w$.$r$.$t the cold junction temperature of $0C)$ being equal to $20$ mV $.$

a$.$ Determine the correction which must be made to the indicated emf if the cold junction temperature is $20C$

b$.$ If the indicated emf is $8\mathrm{.}90$ mV $($w$.$r$.$t the cold junction temperature of $20C)$ in the thermocouple circuit, determine the temperature of the hot junction.