A: The magnetic field lines also represent the lines of force on a moving charged particle at every point.
R: Force on a moving charge acts parallel to the magnetic field.

Options

A. If both Assertion & Reason are the true and the reason is the correct explanation of the assertion, then mark (1)
B. If both Assertion & Reason are true but the reson is not the correct explanation of the assertion, then mark (2)
C. If Assertion is true statement but Reason is false, then mark (3)
D. If both Assertion and Reason are false statements, then mark (4)

Answer

To analyze the given statements regarding magnetic fields and forces on moving charged particles, we will break down the assertion (A) and the reason (R) step by step.

### Step-by-Step Solution:

1. **Understanding Assertion (A)**:
- The assertion states that "the magnetic field lines also represent the lines of force on a moving charged particle at every point."
- Magnetic field lines indicate the direction of the magnetic field at any point in space. However, they do not represent the lines of force acting on a moving charged particle. The force experienced by a charged particle is determined by the magnetic field and its velocity.

2. **Understanding the Reason (R)**:
- The reason states that "the force on a moving charge acts parallel to the magnetic field."
- This statement is incorrect. The force on a moving charge in a magnetic field is given by the Lorentz force law, which states that the force (F) is given by:
\[ F = q(\mathbf{v} \times \mathbf{B}) \]
where \(q\) is the charge, \(\mathbf{v}\) is the velocity vector of the charge, and \(\mathbf{B}\) is the magnetic field vector. The cross product indicates that the force is perpendicular to both the velocity of the charge and the magnetic field.

3. **Conclusion**:
- Since the assertion (A) is incorrect (magnetic field lines do not represent the lines of force on a moving charged particle) and the reason (R) is also incorrect (the force is not parallel to the magnetic field but rather perpendicular), we conclude that both statements are false.

4. **Final Answer**:
- Therefore, the correct answer is that both the assertion (A) and the reason (R) are incorrect.