Consider the motion of a positive point charge in a region where area simultaneous uniform electric and magnetic fields ` vec(E) = E_(0) hat(j)` and ` vec(B) = B_(0) hat(j)`. At time ` t = 0` , this charge has velocity ` vec(v)` in the ` x-y `plane , making an angle ` theta` with the ` x-axis `. Which of the following option(s) is (are) correct for time ` t gt 0`?

Options

A. If `theta = 0^(@)`, the charge moves in a circular path in the x -z plane.
B. If `theta = 0^(@)`, the charge undergoes helical motion with constant pitch along the Y-axis.
C. If `theta = 10^(@)` the charge undergoes helical motion with its pitch increasing with time, along the Y-axis.
D. If `theta = 90^(@)` , the charge undergoes linear but accelerated motion along the Y-axis.

Answer

c

Explanation

The path will be helical and due to electric field applied along the magnetic field its pitch will go on increasing. Hence option (c) is correct