The north pole of a bar magnet is rapidly introduced into a solenoid at one end (say A). Which of the following statements correctly depicts the phenomenon taking place?

Options

A. No induced emf is developed.
B. The end A of the solenoid behaves like a south pole.
C. The end A of the solenoid behaves like north pole.
D. The end A of the solenoid acquires positive potential.

Explanation

To solve the question regarding the introduction of the north pole of a bar magnet into a solenoid, we can break down the phenomenon into several steps:

### Step-by-Step Solution

1. **Understanding the Setup**:
- We have a solenoid, which is a coil of wire wound in a helical shape. When a magnetic field is applied, it can induce a magnetic field in the solenoid.
- A bar magnet is introduced into the solenoid with its north pole facing the solenoid.

2. **Applying Lenz's Law**:
- According to Lenz's Law, the direction of induced current in a closed loop is such that it opposes the change in magnetic flux through the loop.
- In this case, as the north pole of the bar magnet approaches the solenoid, the magnetic flux through the solenoid increases.

3. **Induction of Current**:
- To oppose the increase in magnetic flux due to the approaching north pole, the solenoid will induce a current.
- The direction of this induced current will be such that it creates a magnetic field opposing the incoming magnetic field of the bar magnet.

4. **Behavior of the Solenoid's Ends**:
- The end of the solenoid that faces the approaching north pole (let's call it end A) will behave like a north pole as well.
- This is because the solenoid generates a magnetic field that opposes the incoming north pole, which results in end A of the solenoid acting as a north pole.

5. **Conclusion**:
- Therefore, the correct statement is that the end A of the solenoid behaves like a north pole, which repels the approaching north pole of the bar magnet.

### Final Answer:
The end A of the solenoid behaves like a north pole, opposing the motion of the north pole of the bar magnet.

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