As shown in the figure,two solenoids are in line.The switch S,initially closed,is suddenly opened.Just after opening S,what is the polarity of the induced emf in terminals X and Y?
A)X and Y are at the same potential.
B)X is positive and Y is negative.
C)Y is positive and X is negative.

Question

As shown in the figure,two solenoids are in line.The switch S,initially closed,is suddenly opened.Just after opening S,what is the polarity of the induced emf in terminals X and Y? 
A)X and Y are at the same potential. 
B)X is positive and Y is negative. 
C)Y is positive and X is negative.

Quizplus · Accepted Answer

When the switch S is suddenly opened, the current through the first solenoid decreases rapidly, resulting in an induced emf that opposes the decrease in current direction. This induced emf has a direction from Y to X, causing the potential at X to become higher than that at Y. Therefore, X is positive, and Y is negative.

As Shown in the Figure,two Solenoids Are in Line