The thermo emf of a hypothetical thermocouple varies with the temperature of hot junction as E=a +b ^2 in volts, where the ratio a b is 700^ C . If the cold junction is kept at 0^ C , then the neutral temperature is

Step-by-step solution

E=a +b ^2 so d E d =a+2 b For neutral temperature = _ n , dE d =0 or a+2 b _n=0 or _ n =- a / 2 ~b =-700 / 2=-350^ C As cold junction is at 0^ C so negative neutral temperature can not be possible.