Single Choice

A system $$S$$ consists of two coils $$A$$ and $$B$$. The coil $$A$$ have a steady current $$I$$ while the coils $$B$$ is suspended near by as shown in figure. Now the system is heated as to raise the temperature of two coils steadily, then :

Athe two coils show attraction
Correct Answer
Bthe two coils show repulsion
Cthere is no change in the position of the two coils
Dinduced currents are not possible in coil $$B$$

Solution

Coil A carries a steady current with increase in temperature, its resistance increases and so current is decreasing at a constant rate, this induces an emf in B which oppose this change i.e., current in coil B is in same direction of A, therefore they attract to each other.
So, the two coils show attraction


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