Question

An electric charge on the z-axis oscillates sinusoidally about the origin. A distant observer is located at a point on the +x axis. At the observer's location, what are the directions of

a) The electric field oscillation

b) The magnetic field oscillation

c) The electromagnetic wave propagation?

Answer 1

a) The direction of electric field oscillation is same as the direction of oscillation of charge. therefore the electric field oscillates in z-direction.

b) the magnetic is perpendicular to both electric field and direction of propogation. As observer is seeing the oscillation from x axis the direction of propogation should be x axis. Therefore magnetic field oscillates in y-direction.

c) as mentioned above observer is seeing from x axis and wave propogates in straight line. Thus the wave is propogating in x direction.

If you have any doubt related to the answer please let me know in comments. Give a thumbs up if you like the answer.