Question

Which of the following statements is/are correct regarding a current-carrying solenoid?

• A. The magnetic field lines outside a solenoid are in the form of parallel straight lines.
• B. The magnetic field lines inside a solenoid are in the form of parallel straight lines.
• C. The strength of the magnetic field increases with an increase in the current.
• D. The strength of the magnetic field decreases with an increase in the current.

Answer 1

Answer: (B), (C)

The strength of the magnetic field increases with an increase in the current.

A current-carrying solenoid behaves similar to a bar magnet. The magnetic field inside solenoid is uniform and thus, the magnetic field lines inside the solenoid are in the form of parallel straight lines. Whereas, outside the magnet, the magnetic field lines are curved.
Also, the strength of the magnetic field of a solenoid increases with an increase in the current.