A region has uniform electric and magnetic fields along the positive `x`-direction. An electron is fired from the origin at an angle `theta( lt 90^(@))` with the x-axis. It will
(i) move along a helical path of increasing pitch
(ii) move along a helical path of decreasing pitch initially
(iii) return to the `yz` plane at some time
(iv) come to rest momentarily at some position

Options

A. move along a helical path of increasing pitch
B. move along a helical path of decreasing pitch initially
C. return to the origin after some time
D. come to rest momentarily at some position

Answer

B,C

Explanation

The eletric field exerts a force opposite to the component of motion along the `x-` axis.