Question 360: Current Electricity

Question

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

Accepted Answer

Neutral temperature is the temperature of a hot junction at which $$E$$ is maximum.
$$ \Rightarrow {{dE} \over {d	heta }} = 0$$
or $$a + 2b	heta  = 0 \Rightarrow 	heta  = {{ - a} \over {2b}} =  - 350$$
Neutral temperature can never be negative hence no $$	heta $$ is possible.

Answer

$${1400^ \circ }C$$

Answer

$${350^ \circ }C$$

Answer

$${700^ \circ }C$$

Answer

No neutral temperature is possible for this termocouple.

Current Electricity

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

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