Question

Assertion (A): When two dissimilar metals are joined across the junction and maintained at different temperature a potential difference is developed.

Reason (R): Electrons drift from one metal to the other.

• A. Both A and R are true and R is correct explanation of A
• B. Both A and R are true and R is not correct explanation of A
• C. A is true R is false
• D. A is false R is true

Answer 1

The correct option is C A is true R is false

Seebeck Effect from electron theory: Metals contain a large number of free electrons that behave like a perfect gas and when we join two dissimilar metals at different temperature a potential difference is developed. This effect is called Seebeck effect. Electrons diffuse from metal of higher electron density to that of lower density and the resultant emf causes a flow of electrons in the circuit.

Thus, Seebeck effect is due to the imbalance in potential difference between the hot and old junctions.