Current Electricity - Result Question 43
45. The rate of increase of thermo-e.m.f. with temperature at the neutral temperature of a thermocouple
[2011]
(a) is positive
(b) is zero
(c) depends upon the choice of the two materials of the thermocouple
(d) is negative
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Answer:
Correct Answer: 45. (b)
Solution:
- (b) We have, $e=at+bt^{2}$
$\Rightarrow \frac{de}{dt}=a+2 bt$
At neutral temperature,
$t=-\frac{a}{2 b}$
$\therefore \frac{de}{dt}=0$
