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Electricity and Magnetism

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Electron in Parallel Magnetic and Electric Fields

EANDM-JJFUE1

An electron starts at rest at the origin in a region with uniform magnetic and electric fields given by $\vec E = E_0 \: \widehat x$ and $\vec B = B_0 \:\widehat x$ where $E_0$ and $B_0$ are both positive.

Which of the following statements best describes the subsequent motion of the electron?

A

The electron will remain at rest.

B

The electron will be accelerated in the $- \widehat x$ direction by the electric field and move in a helical path about the $- \widehat x$ direction because of the magnetic field.

C

The electron will be accelerated in the $- \widehat x$ direction by the electric field, but it will be unaffected by the magnetic field.

D

The electron will move in circular motion in the $\widehat y - \widehat z$ plane.

E

The electron will be accelerated in the $ \widehat x$ direction only.