Question

Mention any two properties of magnetic field lines. Define Maxwell's cork-screw rule for finding direction of magnetic field due to a straight current carrying wire. Depict the magnetic field lines due to a vertical current carrying conductor. Show uniform magnetic field in a given region.

Hint:

Magnetic field lines around a straight conductor are always circular and can be determined using Maxwell's cork-screw rule. In a uniform magnetic field, the lines are parallel and equally spaced.

Answer 1

Properties of Magnetic Field Lines:
1. Magnetic field lines are closed loops: The magnetic field lines form closed loops. They never intersect and always loop from the north pole of a magnet to the south pole outside and from south to north inside the magnet. 2. Density of field lines represents the strength of the magnetic field: The closer the magnetic field lines are to each other, the stronger the magnetic field at that point. A larger spacing between the lines indicates a weaker magnetic field.
Maxwell's Cork-Screw Rule:
Maxwell's cork-screw rule is a method to determine the direction of the magnetic field due to a current-carrying conductor. According to this rule, if you hold a right-handed screw in your right hand and move it in the direction of current, the direction in which the screw turns will represent the direction of the magnetic field lines.
Magnetic Field Lines due to a Vertical Current-Carrying Conductor:
When a current flows through a straight conductor, it creates a circular magnetic field around the conductor. The direction of the magnetic field lines can be determined by Maxwell's cork-screw rule.

Uniform Magnetic Field in a Given Region:
A uniform magnetic field is one where the magnetic field lines are parallel, equidistant, and extend in one direction. A common example is the magnetic field between the two poles of a bar magnet or in a solenoid.
Conclusion:
The magnetic field lines around a current-carrying conductor form closed loops, and Maxwell's cork-screw rule is an effective way to find the direction of these magnetic fields. A uniform magnetic field is characterized by parallel and equidistant lines.