# Thomson effect

## Thomson effect

- Thomson effect is related to the emf that develops between two parts of the single metal when they are at different temperature

- Thus Thomson effect is the absorption or evolution of heat along a conductor when current passes through it when one end of the conductor is hot and another is cold

- If two parts of the metal are at small temperature difference dT ,then the electric potential difference is proportional to dT
dV α dT

or

dV=σdT

where σ is the constant of proportionality and is known as Thomson coefficient

- Peltier coefficient and Thomson coefficient are related to thermo-power according to following relations

π=Ts=T(dE/dT)

and σ =-T(ds/dT)=-T(d^{2}E/dT^{2})

- We have seen that all the three effects are defined in terms of three coefficient namely Seaback,Peltier and Thomson coefficient but the basic quantity is thermo-power which is the rate of change of thermo-emf with temperature

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