Finally, the switch on the electromagnet is reopened. The magnitude of the external magnetic flux through the wire loop (A. increases, B. decreases, C. remains constant), and there is (A. zero, B. a clockwise, C. a counterclockwise) current induced in the loop (as seen from the left). Enter the letters corresponding to the responses that correctly complete the statement
The Correct Answer and Explanation is :
The correct answer is:
B. decreases
B. a clockwise
Explanation:
This scenario involves the concept of electromagnetic induction, which is governed by Faraday’s Law of Induction. Faraday’s Law states that a change in magnetic flux through a circuit induces an electromotive force (EMF), and if the circuit is closed, this EMF drives a current. The induced current’s direction is determined by Lenz’s Law, which states that the induced current will flow in a direction that opposes the change in magnetic flux that caused it.
In this case, when the switch on the electromagnet is reopened, the magnetic field generated by the electromagnet starts to decrease because the current supplying the electromagnet is interrupted. This results in a decrease in the external magnetic flux through the wire loop. Therefore, the magnetic flux decreases.
As the magnetic flux decreases, according to Faraday’s Law, an induced EMF is generated in the wire loop. Lenz’s Law tells us that the induced current will flow in such a way as to oppose the decrease in the magnetic flux. Since the magnetic flux due to the electromagnet is decreasing, the induced current will flow in the opposite direction to create its own magnetic field that opposes the reduction in flux. This is why the current is induced in a clockwise direction when viewed from the left (as it tries to maintain the magnetic flux in the loop).
In summary:
- The external magnetic flux through the wire loop decreases as the electromagnet is turned off.
- The induced current flows in a clockwise direction to oppose the decrease in flux and maintain the magnetic field.