Which one of the following is not correct about Lorentz Force?

Options

A. In presence of electric field `vecE(r)` ang magnetic field `vecB(r)` the force on a moving electric charge is `vecF=q[vecE(r)+vecvxx vecB(r)]`
B. The force, due to magnetic field on a negative charge is opposite to that on a positive charge.
C. The force due to magnetic field becomes zero if velocity and magnetic field are parallel or anti- parallel.
D. For a static charge the magnetic force is maximum.

Explanation

To determine which statement about the Lorentz force is incorrect, we will analyze each statement based on the principles of electromagnetism.

### Step-by-Step Solution:

1. **Understanding the Lorentz Force**:
The Lorentz force \( \mathbf{F} \) acting on a charged particle moving in electric and magnetic fields is given by the equation:
\[ \mathbf{F} = q \mathbf{E} + q (\mathbf{v} \times \mathbf{B}) \]
where \( q \) is the charge of the particle, \( \mathbf{E} \) is the electric field, \( \mathbf{v} \) is the velocity of the charge, and \( \mathbf{B} \) is the magnetic field.

2. **Analyzing Statement 1**:
Statement 1 claims that in the presence of electric field \( \mathbf{E} \) and magnetic field \( \mathbf{B} \), the force on a moving electrical charge is given by the Lorentz force equation.
- **Conclusion**: This statement is **correct**.

3. **Analyzing Statement 2**:
Statement 2 states that the force due to a magnetic field on a negative charge is opposite to that of a positive charge.
- The magnetic force on a charge is given by \( \mathbf{F} = q (\mathbf{v} \times \mathbf{B}) \). If \( q \) is negative, the direction of the force will be opposite to that for a positive charge.
- **Conclusion**: This statement is **correct**.

4. **Analyzing Statement 3**:
Statement 3 claims that the force due to the magnetic field becomes zero if the velocity and the magnetic field are parallel or anti-parallel.
- The magnetic force depends on the cross product \( \mathbf{v} \times \mathbf{B} \). If \( \mathbf{v} \) and \( \mathbf{B} \) are parallel or anti-parallel, the cross product is zero, hence the force is zero.
- **Conclusion**: This statement is **correct**.

5. **Analyzing Statement 4**:
Statement 4 asserts that for a static charge, the magnetic force is maximum.
- For a static charge, the velocity \( \mathbf{v} = 0 \), which means the magnetic force \( \mathbf{F} = q (\mathbf{v} \times \mathbf{B}) = 0 \). Therefore, the magnetic force is not maximum; it is zero.
- **Conclusion**: This statement is **incorrect**.

### Final Answer:
The statement that is not correct about Lorentz force is **Statement 4**.

---