Which of the following statements regarding magnetic lines of force is correct ?

Options

A. Total magnetic flux linked a closed surface is always zero
B. They need not perpendicular to the surface from where they start or where they meet
C. They may or may not pass through conductor
D. All of these

Answer

To determine which statement regarding magnetic lines of force is correct, we will analyze each statement provided.

### Step-by-Step Solution:

1. **Understanding Magnetic Flux**:
- The magnetic flux (Φ) through a closed surface is defined as the total number of magnetic field lines passing through that surface. According to Gauss's law for magnetism, the total magnetic flux through any closed surface is always zero. This is due to the fact that magnetic field lines do not begin or end at any point (they are continuous loops).

**Hint**: Recall the property of magnetic field lines and Gauss's law for magnetism.

2. **Evaluating Statement 1**:
- Statement 1 claims that "the total magnetic flux linked to a closed surface is always zero." This is correct based on the explanation above. Therefore, Statement 1 is true.

**Hint**: Think about how magnetic field lines behave in a closed surface.

3. **Evaluating Statement 2**:
- Statement 2 states that "they need not be perpendicular to the surface from where they start or where they meet." This is incorrect. Magnetic field lines are always perpendicular to the surface at the point where they exit or enter. Therefore, Statement 2 is false.

**Hint**: Consider the orientation of magnetic field lines relative to surfaces.

4. **Evaluating Statement 3**:
- Statement 3 claims that "they may or may not pass through a conductor." This is also incorrect. Magnetic field lines typically pass through conductors when they are present in a magnetic field, as the field influences the charges within the conductor. Therefore, Statement 3 is false.

**Hint**: Reflect on how magnetic fields interact with conductors.

5. **Conclusion**:
- After evaluating all the statements, we find that only Statement 1 is correct. Thus, the correct answer is that the total magnetic flux linked to a closed surface is always zero.

### Final Answer:
The correct statement regarding magnetic lines of force is: **"The total magnetic flux linked to a closed surface is always zero."**