Solenoid Magnetic Field Lines Inside

Inside a current-carrying solenoid, the magnetic field lines exhibit a specific pattern.

Focusing on the region near the center of a long solenoid:

• The field lines run parallel to the solenoid's axis.
• The field lines are equally spaced.

This arrangement indicates a uniform magnetic field strength along the central axis.

The field outside the solenoid is significantly weaker and spreads out considerably, differing from the organized pattern inside.

Therefore, the magnetic field lines inside a current-carrying solenoid are characterized as parallel and uniformly spaced.

Option 3 correctly describes this configuration.