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The thermo emf E of a thermocouple is fo...

The thermo emf E of a thermocouple is found to vary wit temperature T of the junction (cold junction is `0^(@)C`) as
`E=40T-(T^(2))/(20)`
The temperature of inversion for the thermocouple is

A

`20^(@)C`

B

`400^(@)C`

C

`-200^(@)C`

D

`-100^(@)C`

Text Solution

Verified by Experts

The correct Answer is:
C
`E=40t+(1)/(10)t^(2)`
At inversion temperature E will be minimum
i.e. `(dE)/(dt)=0`
`(d)/(dt)[40t+ (1)/(10) t^(2)]=0`
`:.t=-200^(@)C`.
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