Question

$$\begin{gathered} Theforce\stackrel{\rightharpoonup }{F}experiencedbyachargeparticlemovingwithvelocity\overrightarrow{v}inamagneticfield\overrightarrow{B}isgivenbytherelation \\ \overrightarrow{F}=q(\overrightarrow{v}\times \overrightarrow{B}).Whichpairamongtheseis/arealwaysatrightangletoeachother? \\ \left(A\right)\stackrel{\rightharpoonup }{F}and\overrightarrow{v}\left(B\right)\overrightarrow{F}and\overrightarrow{B}\left(C\right)\overrightarrow{B}and\overrightarrow{v}\left(D\right)Noneofthese \end{gathered}$$

Answer 1

Dear Student,

The given equation ${\overrightarrow{F}}_m=q\left(\stackrel{\rightharpoonup }{v}\times \overrightarrow{B}\right)$ is the equation for magnetic Lorentz force.
where the direction of force ${\overrightarrow{F}}_m$ is always perpendicular to the plane containing $\overrightarrow{v}and\overrightarrow{B}$ .
i.e., F_m is perpendicular to v as well as B .

Also since F_m acts perpendicular to the motion of charge the work done by it on the moving charge is zero.


So options A and B both are right.




Regards