Question

In the above diagram, a strong bar magnet is moving towards solenoid-2 from solenoid-1. The direction of induced current in solenoid-1 and that in solenoid-2, respectively, are through the directions :

• A. AB and DC
• B. BA and CD
• C. AB and CD
• D. BA and DC

Answer 1

The Correct Option is A

When a strong bar magnet moves towards a solenoid, it induces an electromotive force (EMF) in the solenoid due to electromagnetic induction. The direction of the induced current can be determined using Lenz's Law, which states that the direction of the induced current is always such that it opposes the change in magnetic flux that produced it. Let's analyze the problem step by step:

1. As the bar magnet approaches solenoid-1, the magnetic flux linked with solenoid-1 increases. To oppose this increase, the induced current in solenoid-1 will flow in such a direction that its own magnetic field opposes the field of the approaching magnet.
2. Using the right-hand rule, if the north pole of the bar magnet is moving towards solenoid-1, the induced current in solenoid-1 will flow in direction AB. This creates an induced magnetic field with its north pole facing the approaching bar magnet.
3. Now, consider solenoid-2. As the bar magnet moves away from solenoid-1 and approaches solenoid-2, it causes an increase in magnetic flux linking solenoid-2. Hence, the induced current in solenoid-2 will flow in such a direction that its magnetic field opposes the new incoming magnetic field.
4. Using Lenz's Law again, if we apply the right-hand rule to solenoid-2, the induced current in solenoid-2 will flow in direction DC, creating an induced magnetic field with its south pole facing the bar magnet.

Therefore, the correct option is AB and DC, where the induced current in solenoid-1 flows in direction AB and in solenoid-2 flows in direction DC respectively.

Answer 2

 

 

Step 1: Use Lenz’s Law 

According to Lenz’s law, the induced current always flows in a direction such that it opposes the change in magnetic flux that causes it.

Step 2: Analyze Solenoid-1

As the bar magnet approaches solenoid-1, the magnetic flux increases. To oppose this increase, solenoid-1 generates a magnetic field opposite to the bar magnet’s field, inducing a current in the direction AB.

Step 3: Analyze Solenoid-2

For solenoid-2, the magnetic field due to the approaching bar magnet increases in the direction towards solenoid-1. To oppose this, solenoid-2 generates a magnetic field pointing away, inducing a current in the direction DC.