Correct Option
The correct option is 1 and 2 only.
Explanation
Magnetic field lines are imaginary lines used to represent the magnetic field around a magnet. They provide a visual representation of the direction and strength of the magnetic force at various points in space. A fundamental property of these lines is that they form continuous closed loops.
Statement-wise Analysis
- Statement 1 is Correct: By convention, the magnetic field lines emerge from the North pole and merge at the South pole outside the magnet. This direction indicates the path a hypothetical isolated North pole would take if placed in the field.
- Statement 2 is Correct: Unlike electric field lines, which start from a positive charge and end at a negative charge, magnetic field lines do not have a beginning or an end. Inside the magnet, the direction of the field lines is from the South pole to the North pole, completing the closed loop.
- Statement 3 is Incorrect: The relative strength of the magnetic field is directly represented by the degree of closeness of the field lines. The field is stronger where the lines are crowded (closer together) and weaker where the lines are spaced further apart. Therefore, closeness is dependent on field strength.
- Statement 4 is Incorrect: Two magnetic field lines can never intersect. If they were to intersect, it would imply that at the point of intersection, the magnetic field has two different directions. This is physically impossible, as a compass needle placed at that point can only point in one resultant direction.
Key Takeaway: Magnetic field lines form continuous closed loops (North to South outside; South to North inside), never intersect, and their density indicates the strength of the magnetic field.