Correct Option
The correct option is Both A and R are true and R is the correct explanation of A.
Explanation
A solenoid is a cylindrical coil of many tightly wound turns of insulated wire. When an electric current flows through the solenoid, it generates a magnetic field according to the principles of electromagnetism. The nature of this field dictates the physical properties and interactions of the solenoid.
Statement-wise Analysis
- Assertion (A): Correct. A current-carrying solenoid behaves exactly like a bar magnet. It develops a magnetic polarity, with one face acting as the North Pole and the other as the South Pole. Consequently, it exhibits properties such as directive property (aligning North-South when suspended) and attractive property (attracting ferromagnetic materials).
- Reason (R): Correct. The magnetic field lines produced by a current-carrying solenoid are parallel and uniform inside the coil, while outside, they emerge from one end (North) and enter the other (South), forming closed loops. This spatial distribution of magnetic field lines is identical to that of a bar magnet.
Justification for Explanation: The macroscopic behavior of a magnetic object is determined by its magnetic field configuration. Since the magnetic field pattern of the solenoid is identical to that of a bar magnet, the solenoid exhibits the same physical behavior (attraction, repulsion, alignment). Therefore, the identical field pattern is the fundamental reason for the solenoid's behavior as a bar magnet.
Key Takeaway: A current-carrying solenoid is effectively an electromagnet. Its magnetic moment and dipolar behavior arise because the superposition of magnetic fields from individual current loops creates a field pattern indistinguishable from a permanent bar magnet.