AP® Physics C: E & M

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Moderate

Affect of Charge Sign on Circular Paths in a Magnetic Field

APPHEM-ESKD2G

A particle of charge $\mathit{q}$ and mass $\mathit{m}$ moves in a clockwise circular path of radius $\mathit{r}$ in a uniform magnetic field $\mathit{B}$ at a speed $\mathit{v}$. The particle is replaced with a particle of identical mass and charge $\mathit{-q}$, moving at speed $v$.

The radius and direction of the new circular path the particle makes is:

A

$\mathit{\cfrac{1}{2}r}$, clockwise

B

$\mathit{\cfrac{1}{2}r}$, counter-clockwise

C

$\mathit{r}$, clockwise

D

$\mathit{r}$, counter-clockwise

E

$\mathit{2r}$ clockwise