Which one of the following is correct statement about magnetic forces?

Options

A. Magnetic forces always obey Newton's third law
B. Magnetic forces do not obey Newton's third law
C. For very high current, magnetic forces obey Newton's third law
D. Inside low magnetic field, magnetic forces obey Newton's third law

Explanation

To determine which statement about magnetic forces is correct, we need to analyze the options given in the question.

1. **Understanding Newton's Third Law**: Newton's third law states that for every action, there is an equal and opposite reaction. This means that if an object A exerts a force on object B, then object B exerts a force of equal magnitude and opposite direction on object A.

2. **Analyzing the Options**:
- **Option 1**: "Magnetic forces always obey Newton's third law."
- This suggests that magnetic forces will always have an equal and opposite reaction, which is not true in all scenarios involving moving charges in magnetic fields.
- **Option 2**: "Magnetic forces do not obey Newton's third law."
- This option suggests that there are scenarios where the action-reaction pair does not hold, particularly in the context of moving charges in magnetic fields.
- **Option 3**: "A very high current magnetic forces obey Newton's third law."
- This option implies that at high currents, magnetic forces will obey Newton's third law, which is misleading as the fundamental nature of magnetic forces does not change with current.
- **Option 4**: "Inside low magnetic field the magnetic forces obey Newton's third law."
- This suggests that the strength of the magnetic field influences whether the forces obey Newton's third law, which is not accurate.

3. **Conclusion**: The correct statement is that "magnetic forces do not obey Newton's third law." This is because when a charged particle moves in a magnetic field, it experiences a magnetic force that does not have a corresponding equal and opposite force acting on it in the same frame of reference, especially when considering the finite speed of the particle.

### Final Answer:
The correct statement about magnetic forces is: "Magnetic forces do not obey Newton's third law."