Question

The force $F$ acting on charge $q$ moving with velocity $v$ perpendicular to magnetic field $B$ is:

• A. $F=qvB$
• B. $F=\frac{qv}{B}$
• C. $F=\frac{qB}{v}$
• D. $F=\frac{Bv}{q}$

Answer 1

The correct option is A $F=qvB$

Magnetic force $F=q(v\times B)=qvB\sin \theta$
where $\theta$ is the angle between $v$ and $B$.
Given : $\theta ={90}^o$
Thus, force $F=qvB\times \sin {90}^o=qvB$