Which of the following properties of magnetic line of force differs them from electrostatic lines of force ?

Options

A. These are closed curves
B. These can emit or teminate at any angle to the surface
C. Total flux linked with a close surface is always zero
D. All of these

Answer

To solve the question regarding the properties of magnetic lines of force that differentiate them from electrostatic lines of force, we can analyze the properties one by one.

### Step-by-Step Solution:

1. **Understanding Magnetic Lines of Force**:
- Magnetic lines of force are produced by magnets and represent the direction and strength of the magnetic field.
- They always form closed loops, emerging from the north pole and returning to the south pole.

2. **Understanding Electrostatic Lines of Force**:
- Electrostatic lines of force are produced by electric charges.
- They originate from positive charges and terminate at negative charges. In the case of a single charge, they either diverge (from a positive charge) or converge (to a negative charge).

3. **Property 1: Closed Curves**:
- Magnetic lines of force are always closed curves. This means that they do not have a beginning or an end; they loop back on themselves.
- In contrast, electrostatic lines can start and end at charges (positive and negative), indicating that monopoles can exist in electrostatics (like a single positive or negative charge).

4. **Property 2: Angle of Emission**:
- Magnetic lines of force can intersect surfaces at any angle. They are not restricted to being perpendicular to the surface.
- Electrostatic lines of force, however, are always perpendicular to the surface of a conductor in electrostatic equilibrium.

5. **Property 3: Total Flux**:
- The total magnetic flux linked with a closed surface is always zero. This is because the lines of force that enter the surface also exit it, resulting in no net flux.
- In electrostatics, the total electric flux through a closed surface can be non-zero, depending on the enclosed charge.

6. **Conclusion**:
- The properties that differentiate magnetic lines of force from electrostatic lines of force include:
- Magnetic lines of force are closed curves, while electrostatic lines can start and end at charges.
- Magnetic lines can intersect surfaces at any angle, while electrostatic lines are always perpendicular to the surface.
- The total magnetic flux through a closed surface is zero, while the total electric flux can be non-zero.

### Final Answer:
All of the mentioned properties (closed curves, angle of emission, and total flux being zero) are correct and differentiate magnetic lines of force from electrostatic lines of force.

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