What is Thomson Effect ? (Define)( positive and negative with examples)

Thomson Effect

The absorption or evolution of heat energy, if a current is allowed to flow in a conductor having it's different parts at different temperatures is known as Thomson Effect

 Positive Thomson effect:  

For metals like copper silver, zinc, Antimony and cadmium etc. portion at high temperature is considered at high potential than a portion at lower temperature. Hence heat energy is absorbed when current flows from a point at lower temperature to a point at higher temperature.

Negative Thomson effect: 


For metals like Bismuth,Cobalt,platinum and Nickel portion at high temperature is considered at lower potential than a portion at lower temperature. Hence heat energy is absorbed when current flows from a point at higher temperature to a point at lower temperature.


In case of lead, Thomson effect is not present.