Question

Why can’t two magnetic field lines cross each other? Draw magnetic field lines showing the direction of the magnetic field due to a current-carrying long straight solenoid. State the conclusion which can be drawn from the pattern of magnetic field lines inside the solenoid. 

Hint:

A solenoid produces a uniform magnetic field inside, making it useful as a magnet in various applications. The strength of the magnetic field can be increased by increasing the number of turns or the current.

Answer 1

F₂Why can’t Two Magnetic Field Lines Cross Each Other?
If two magnetic field lines were to cross each other, it would imply that the magnetic field has two different directions at the same point, which is not possible. Therefore, magnetic field lines never intersect.

F₂Magnetic Field Due to a Current-Carrying Long Straight Solenoid:
A solenoid is a coil of wire carrying a current. The magnetic field produced by a solenoid is uniform and parallel inside the solenoid, with the field lines forming straight lines from one end to the other. Outside the solenoid, the field lines are similar to the field of a bar magnet, with distinct north and south poles.

\[ \text{Inside the solenoid:} \quad \text{Uniform magnetic field, parallel lines.} \] \[ \text{Outside the solenoid:} \quad \text{Similar to a bar magnet's field, with loops.} \]
F₂Conclusion from Magnetic Field Lines of a Solenoid:
The magnetic field inside the solenoid is uniform and parallel, and its strength depends on the current in the solenoid and the number of turns per unit length.