Heat and Thermal ExpansionHard

Question

The thermo emf of a thermocouple varies with the temperature θ of the hot junction as E = a θ + bθ2 in volts where the ratio a/b is 700oC. If the cold junction is kept at 0oC, then the neutral temperature is

Options

A.700oC
B.350oC
C.1400oC
D.no neutral temperature is possible for this thermocouple.

Solution

E = aθ + bθ2
At neutral temperature dE/dθ = 0
∴     = a + 2bθn = 0; θn = -
Now = 700oC(given)
θn = - 700/2 = - 350oC
Now θc = 0oC
So, θn > 0oC
But mathematically θn < 0oC

Create a free account to view solution

View Solution Free
Topic: Heat and Thermal Expansion·Practice all Heat and Thermal Expansion questions

More Heat and Thermal Expansion Questions

Two wires are made of the same material and have the same volume. However wire 1 has crosssectional area A and wire-2 ha...The figure shows two thin rods, one made of aluminum [&#945; = 23 &#215; 10-6 (Co)-1] and the other of steel [&#945; = 1...The figure shows two rods, one made of aluminum [&#945; = 23 &#215; 10-6 (Co)-1] and the other of steel [&#945; = 12 &#2...A brass wire of length 2 m and radius 1 mm at $27^{\circ}C$ is held taut between two rigid supports. Initially it was co...Certain prefect gas is found to obey PVn = constant during adiabatic process. The volume expansion cofficient at tempera...