Question

The force on a charged particle moving through a magnetic field is maximum when

• A. Moving with the field
• B. Moving against the field
• C. Moving at a ${45}^{\circ }$ angle to the field
• D. Moving at a ${90}^{\circ }$ angle to the field
• E. The particle will not be affected

Answer 1

Answer: (D)

Moving at a ${90}^{\circ }$ angle to the field

Magnetic force on the charged particle $F_m=q(\overrightarrow{v}\times \overrightarrow{B})=qvB$ $sin\theta$

where $\theta$ is the angle between $\overrightarrow{v}$ and $\overrightarrow{B}$

$\therefore$ $F_m$ is maximum when $sin\theta =1$ OR $\theta ={90}^o$

Thus magnetic force on charged particle is maximum when it moves at a ${90}^o$ angle to the field.