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AP® Physics C: E & M

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Moderate

Proton Enters Magnetic Field

APPHEM-J6NEWI

A proton enters a uniform magnetic field with a path perpendicular to the field lines and moves in a circular path of radius $R$. An electron enters the same magnetic field at the same speed in a path perpendicular to the field.

Compared to the proton’s path, the radius of the electron’s circular path is:

A

the same radius.

B

a larger radius.

C

a smaller radius.

D

the electron moves in a straight line.