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(d2E/dT2)
• 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