Question

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

• A. In presence of electric field and magnetic field the force on a moving electric charge is $\overrightarrow { \mathrm { F } } = \mathrm { q } [ \overrightarrow { \mathrm { E } } ( \mathrm { r } ) + \mathrm { v } \times \overrightarrow { \mathrm { B } } ( \mathrm { r } ) ]$
• 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 become zero of velocity and magnetic field are parallel or anti-parallel.
• D. For a static charge the magnetic force is maximum.

Answer 1

Answer: (D)

For a static charge the magnetic force is maximum.

Answer 2

If charge is not moving then the magnetic force is zero.

Since

As for stationary charge

$\therefore \overrightarrow { \mathrm { F } } _ { \mathrm { m } } = 0$