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The thermo emf of a thermocouple varies with the temperature of the 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

Options

  1. A700^ C
  2. B350^ C
  3. C1400^ C
  4. Dno neutral temperature is possible for this thermocouple.

Correct answer

D. no neutral temperature is possible for this thermocouple.

Step-by-step solution

E=a +b ^2 At neutral temperature dE / d =0 dE d = a +2 ~b _ n =0 ; _ n =- a 2 ~b Now a b =700^ C (given) _n=-700 / 2=-350^ C Now _c=0^ C . So, _n>0^ C But mathematically _ n < 0^ C .

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