Question

The magnetic field inside a solenoid carrying current.

• A. is the same at all points
• B. is zero at all points
• C. becomes zero at its north pole
• D. becomes zero at its south pole

Answer 1

The correct option is A is the same at all points

Answer is A.
A solenoid is a tightly wound helical coil of wire whose diameter is small compared to its length. The magnetic field generated in the center, or core, of a current carrying solenoid is essentially uniform, and is directed along the axis of the solenoid. Outside the solenoid, the magnetic field is far weaker. The solenoid is wound from a single helical wire which carries a current I. The winding is sufficiently tight that each turn of the solenoid is well approximated as a circular wire loop, lying in the plane perpendicular to the axis of the solenoid, which carries a current I.