The temperature of the cold junction of the thermocouple is `^(@)C` and the temperature of the hot junction is `T^(@)C`. The relation for the thermo emf is given by, `E = AT = (1)/(2) BT^(2)` ltbRgt (when `A = 16` and `B = 0.08)`. The temperature of inversion will be

Options

A. `500^(@)C`
B. `400^(@)C`
C. `600^(@)C`
D. `460^(@)C`

Answer

B

Explanation

(b) Let temperature of cold junction be `0^(@)C` and the of hot junction be `(T^(@)C)`.
The relation for thermo emf is given as `E = AT = (1)/(2) BT^(2)`
Given, `A = 16, B = 0.08`
`:. E = 16 T = (1)/(2) xx 0.08 xx T^(2)`
Since emf is zero at temperature of inversion we have
`0 = 16 T - 0.04 T^(2) implies T = (16)/(0.04) = 400^(@)C`